text:
•https://doi.org/10.1364/OME.427952
The visible and near-infrared optical absorption coefficient spectrum of Parylene C measured by transmitting light through thin films in liquid filled cuvettes
James A. Guggenheim, Yuanyuan Lyu, Dylan M. Marques, Edward Z. Zhang, and Paul C. Beard
James A. Guggenheim,1,2,* Yuanyuan Lyu,1 Dylan M. Marques,1 Edward Z. Zhang,1,3 and Paul C. Beard1,3
1Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
2Current address: Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
3Wellcome/EPSRC Centre for Surgical and Interventional Sciences (WEISS), University College London, Gower Street, London, WC1E 6BT, UK
*Corresponding author: j.guggenheim@ucl.ac.uk
James A. Guggenheim https://orcid.org/0000-0003-4295-0525
Yuanyuan Lyu https://orcid.org/0000-0001-8646-5623
Dylan M. Marques https://orcid.org/0000-0003-2666-5900
J Guggenheim
Y Lyu
D Marques
E Zhang
P Beard
James A. Guggenheim, Yuanyuan Lyu, Dylan M. Marques, Edward Z. Zhang, and Paul C. Beard, "The visible and near-infrared optical absorption coefficient spectrum of Parylene C measured by transmitting light through thin films in liquid filled cuvettes," Opt. Mater. Express 11, 3854-3869 (2021)
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Organics and Polymers
Attenuation coefficient
Thin film devices
Waveguide sensors
Revised Manuscript: September 2, 2021
Suppl. Mat. (1)
Equations (12)
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Parylene C (PPXC) is a polymer deposited from the gas phase to form optically clear thin films used in devices including waveguides and sensors. The performance of these devices depends on the visible and near infrared absorption coefficient of PPXC. However, the absorption coefficient is difficult to measure. This is because PPXC films are typically too thin to exhibit detectable absorption in conventional transmittance measurements. To address this challenge, a method involving measuring the transmittance of multiple films immersed together in a liquid filled cuvette was devised. This increased the sensitivity to absorption by increasing the path length in PPXC, while also minimizing reflections and surface losses. Using 200-500 µm thick films, this method was applied to measure the absorption coefficient of PPXC at wavelengths in the range 330-3300 nm. The coefficient was found to vary spectrally by more than two orders of magnitude from 0.025 mm-1 at 1562 nm to 7.7 mm-1 at 3262 nm. These absorption measurements could aid the design of PPXC based sensors and waveguides. The method could be useful for measuring the absorption coefficient of other thin, low-loss materials, particularly those for which it is challenging to obtain thick samples such as other polymers deposited from the gas phase in a similar manner to PPXC.
Polyparachloroxylylene (PPXC) [1], also known as Parylene C, is a polymer that usually exists in the form of thin (sub-100 µm thick) films fabricated via chemical vapor deposition. These films are commonly used to provide protective barrier coatings for implanted medical devices [2], optoelectronics [3] and other components, affording properties such as biocompatibility and moisture resistance [2]. In optics, PPXC films are also used to provide a light transmitting layer in devices such as waveguides [4–8] and resonant optical sensors [9–12]. The applications of PPXC based optical devices are diverse, spanning fields including neurophotonics and biomedical imaging. For example, PPXC waveguides have been proposed for transmitting light into the brain for optogenetic stimulation and neuroimaging at a range of visible wavelengths [6,8]. Elsewhere, PPXC based sensors have been developed for use as temperature probes [12] and ultrasound detectors used in photoacoustic imaging [9–11].
In the above applications, the role of PPXC is to transmit light from one place to another and the transmission efficiency affects the device performance. For example, in PPXC based optogenetic waveguides [6], sufficient light must be transmitted through the waveguide to elicit neuronal activation [13]. Likewise, in optically resonant ultrasound sensors made from PPXC [9–11], light must be transmitted efficiently, back-and-forth through a PPXC layer to provide high sensitivity. As the transmissivity of PPXC underpins the performance of these devices, there is a need to quantify light absorption in PPXC.
PPXC films typically appear visually transparent [3]. However, this is not because the films are non absorbing but because they have a low thickness. The combination of this low thickness and a sufficiently low absorption coefficient means almost no light is lost when transmitted once through a film at normal incidence. In the above mentioned devices however, light must commonly travel distances orders of magnitude larger than the PPXC film thickness. In waveguides, this can occur because the light travels parallel to the film plane [4–7]. In optically-resonant sensors, it happens because the light makes many (hundreds or even thousands of) round trips inside the PPXC layer [9–12]. In both cases, the path lengths in PPXC can readily exceed several cm, over which distances optical losses accumulate to the extent that they impact upon the device performance [4,5,7]. Predicting the limits of the performance of these devices, the maximum transmissivity of waveguides or sensitivity of sensors for example, therefore requires accurately quantifying the absorption coefficient of PPXC. Due to the range of different wavelengths used in PPXC based optical devices (e.g. 450-680 nm [4–7] and 1440-1640 nm [9–12,14]), this coefficient is of interest at a broad range of wavelengths throughout the visible and near infrared spectrum.
PPXC absorption has been studied previously. However, previous measurements do not provide an accurate visible and near infrared PPXC absorption coefficient spectrum. In one study, Bera et al. [15] studied the relative spectral characteristics of PPXC absorption using measurements of the total transmittance of a 46 µm thick PPXC film at wavelengths of 280-500 nm, before and after irradiating the film using UV light to study its subsequent discoloration [15]. Elsewhere, Jeong et al. [3] also reported a PPXC transmittance spectrum, spanning the wavelength range 200-1000 nm. Aside from the limited wavelength ranges of these measurements, their main limitation is that they were not corrected for Fresnel reflections, as such they quantify losses that are not specific to absorption. The measurements also suffered limited accuracy due to the low thicknesses of the studied films, particularly at wavelengths where PPXC is highly transparent. For these reasons, it is challenging to estimate the absolute PPXC absorption coefficient from these measurements.
In another study, Xie et al. [8] measured a PPXC absorption coefficient of 0.17 mm-1 by transmitting blue LED light through multiple PPXC films with thicknesses in the range 15-100 µm. It is difficult to ascertain the accuracy of this coefficient however, because the custom system was unconventional and not characterized.
Two other studies reported PPXC attenuation coefficients calculated from estimates of the light intensity transmitted along PPXC waveguides [5,6]. In these studies, a camera was used to image the light scattered out of the side wall of the waveguide, and an exponential function was fitted to the out-scattered intensity as a function of distance along the waveguide. Reddy and Chamanzar [5] used this method to estimate the attenuation in a handful of PPXC waveguides using light with a wavelength of 532 nm. Reddy et al. [6] then applied the same method to characterize a larger number of PPXC waveguides at wavelengths of 450 nm, 532 nm, 633 nm and 680 nm. It is difficult to assess the validity of these measurements however. The main reason is the accuracy of the measurement method is unknown and does not appear to have been investigated. In addition, the reported details of the measurement systems were incomplete, the system was not characterized, and none of the measurements were independently verified. Moreover, across the two studies, only one image was shown of the out-scattered light intensity along a waveguide [5], and this had a low signal to noise ratio (SNR), exhibiting variations on the order of 50-100% of the measured intensity, with no apparent resemblance to an exponential trend as expected in the data. Finally, absorption was evidently not the only loss mechanism, because some light was scattered out of the waveguide.
Given the uncertain accuracy and limited wavelength range of previous PPXC absorption measurements, there is a need to accurately measure the visible and near infrared absorption coefficient spectrum of PPXC.
The main challenge associated with measuring the absorption coefficient of thin, highly transparent PPXC films is that the absorption related losses are often so low that they simply cannot be detected using conventional transmittance measurements [16–19]. In principle, this could be straightforwardly addressed by using a much thicker film. However, it is challenging to fabricate PPXC films that are thick enough to provide accurate measurements.
To address this challenge, a new method was developed. This method extends the approach of Heitmann [19], who measured the internal transmittance of weakly absorbing glass samples by immersing single samples in liquid-filled cuvettes to reduce the refractive index contrast at the sample interfaces. This minimized reflections and surface scattering, increasing the accuracy of subsequent absorption calculations. In the present study, Heitmann's approach is extended to immersing multiple PPXC films in the same liquid-filled cuvette. As well as minimizing reflections and surface scattering, using multiple films increases the path length in PPXC, thereby increasing the detectability of absorption related losses, without requiring a thicker sample. As another means of increasing the total path length and thus the sensitivity, PPXC films with a high thickness of 200-500 µm were custom fabricated. Measurements involving up to ten of these films enabled transmittance measurements to be made with path lengths of up to 5 mm. Measurements were made in the wavelength range 330-3300 nm.
The remainder of the paper details the method and describes its application to measuring the absorption coefficient of PPXC. Section 2 explains the theoretical basis for the method. Section 3 describes how it was applied to measure the absorption coefficient of PPXC. Section 4 presents the results including the absorption spectrum of PPXC. Sections 5 and 6 provide discussions and conclusions.
From Lambert's law, the absorption coefficient of a homogeneous non-scattering material is:
(1)$$ {\mu ={-} \frac{{\log \tau }}{d},}$$
where $\tau $ is the internal transmittance (the transmittance excluding losses due to reflections at the entrance and exit surfaces [29]) of the material over a path length d.
Equation (1) allows calculating the absorption coefficient of a thin film material from a measurement of its internal transmittance. In a conventional transmittance measurement, light could be transmitted through a film at normal incidence as shown in Fig. 1(a). Neglecting multiple internal reflections and any scattering due to surface imperfections, the intensity transmitted through the film would be:
(2)$$ {{T_\textrm{f}} = {\mathrm{\tau }_\textrm{f}}\; \textrm{F}_{\textrm{air} \to \textrm{film}}^2,}$$
where ${\mathrm{\tau }_\textrm{f}}$ is the internal transmittance of the film and ${\textrm{F}_{\textrm{air} \to \textrm{film}}} = {\textrm{F}_{\textrm{film} \to \textrm{air}}}$ is the interfacial Fresnel transmission coefficient of its surfaces, defined using the Fresnel equation:
(3)$$ {{\textrm{F}_{1 \to 2}} = \left( {\frac{{4{\textrm{n}_1}{\textrm{n}_2}}}{{{{({{\textrm{n}_1} + {\textrm{n}_2}} )}^2}}}} \right),}$$
where ${n_1}$ and ${n_2}$ are the refractive indices of the media (labelled 1 and 2) on either side of the interface, in this case the film material and air.
Fig. 1. Schematics showing a beam of light transmitted through (a) a film, free-standing in air, (b) a liquid-filled cuvette containing four films (c) a liquid-filled cuvette without films.
Equation (2) and 3 allow calculating the absorption coefficient of a film from a conventional transmittance measurement. However, if the film is weakly absorbing and thin, this method can provide insufficient sensitivity to absorption. Due to the presence of two closely spaced high-contrast optical interfaces presented by the film surfaces, the method is also susceptible to errors associated with (i) multiple internal reflections, which are not accounted for in Eq. (2) (ii) inaccuracy in the knowledge of the refractive index of the film, which propagates to inaccuracy in the Fresnel coefficients (iii) surface scattering due to film imperfections (iv) deviations from a collimated, normally incident beam.
If, instead, light is transmitted through $m\; $ films immersed in a liquid filled cuvette as shown in Fig. 1(b) (for $m = 4$), then the light will be absorbed in the liquid, in the cuvette walls, and in the films, and partially reflected at each of the air-cuvette, cuvette-liquid and liquid-film interfaces. Therefore, neglecting multiple internal reflections and scattering due to surface imperfections, the total transmittance can be written as:
(4)$$ {{T_m} = {\tau _c}{\tau _f}\; {e^{ - {\mu _l}({L - D} )}}\; \textrm{F}_{\textrm{air} \to \textrm{cuvette}}^2\textrm{F}_{\textrm{cuvette} \to \textrm{liquid}}^2\textrm{F}_{\textrm{film} \to \textrm{liquid}}^\textrm{m},}$$
where: ${\tau _c}$ is the total internal transmittance of both of the cuvette walls, defined by the wall thicknesses and the absorption coefficient of the cuvette wall material; ${\tau _f} = {e^{ - {\mu _f}D}}$ is the internal transmittance of the film material accumulated across all the films, where D is the total path length in the film material, defined as $D = \mathop \sum \limits_{i = 1}^m {d_i}$, where ${d_i}$ is the thickness of each film, and ${\mu _f}$ is the film absorption coefficient; ${e^{ - {\mu _l}({L - D} )}}$ is the internal transmittance of the liquid, where ${\mu _l}$ is the absorption coefficient of the liquid and L is the cuvette path length; and the $\textrm{F}$ terms, defined as in Eq. (3), describe the transmissivities of the different optical interfaces in the sample.
Equation (4) permits calculating the internal transmittance of the film material from a single transmittance measurement, given knowledge of the absorption coefficient of the cuvette wall material and the liquid, and the refractive index and total thicknesses of the liquid, cuvette wall, and film materials. The calculation can be simplified however, its accuracy improved, and the need for knowledge of the cuvette material obviated, by performing a reference measurement. This requires removing the films so the cuvette contains liquid only, as shown in Fig. 1(c). The total transmittance is now:
(5)$$ {{T_0} = {\tau _c}\; {e^{ - {\mu _l}L}}\; \textrm{F}_{\textrm{air} \to \textrm{cuvette}}^2\; \textrm{F}_{\textrm{cuvette} \to \textrm{liquid}}^2,}$$
Dividing Eq. (5) by Eq. (4) yields:
(6)$$ {\frac{{{T_0}}}{{{T_m}}} = \frac{{{e^{ - {\mu _l}D}}}}{{{\mathrm{\tau }_\textrm{f}}\,\textrm{ F}_{\textrm{film} \to \textrm{liquid}}^\textrm{m}}},}$$
which, rearranged, provides the following expression for the internal transmittance of the film:
(7)$$ {{\mathrm{\tau }_\textrm{f}} = \frac{{{T_m}\; }}{{{\textrm{T}_0}}}C,}$$
in which the term
(8)$$ {C = \frac{{\; {e^{ - {\mu _l}D}}}}{{\textrm{F}_{\textrm{film} \to \textrm{liquid}}^\textrm{m}}}}$$
can be considered a correction for measured losses unrelated to film absorption.
Using Eq. (1) and Eq. (7), the absorption coefficient of a film material can be determined from measurements of ${T_0}$ and ${T_m}$, given knowledge of the absorption coefficient of the liquid, the thickness of the films, and the refractive indices of the liquid and the film material. Compared to estimating the absorption coefficient of a weakly-absorbing thin film material from the transmittance of a single film in air, this has two advantages. Firstly, using multiple films extends the path length in the film material, increasing the sensitivity to absorption. Secondly, immersing the films reduces the refractive index at the film surfaces, reducing the magnitude of reflections and thus the size and impact of (i) higher order reflections (ii) errors in the calculated surface transmissivity (iii) surface scattering. In the limit where the liquid is negligibly absorbing and the indices of the film and liquid are identical, C goes to 1 and the absorption coefficient of the film can be obtained directly from the ratio of the two transmittance measurements.
To summarize, the above constitutes an alternative method for measuring the absorption coefficient of a weakly absorbing thin film material that can, in principle, provide significantly higher accuracy than a conventional transmittance measurement.
3.1 PPXC film preparation
PPXC films were fabricated using a commercial PPXC deposition system (PDS 2010 Labcoater 2, Speciality Coating Systems). To increase the sensitivity of the absorption measurements, the films were fabricated with a relatively high thickness of 200-500 µm as follows. Firstly, a thin PPXC film was grown on a polymethylmethacrylate (PMMA) substrate. This film was peeled from the substrate, then returned to the deposition system, suspended on a hollow frame such that PPXC could then be grown on both sides of the film simultaneously over several further deposition runs. Doing this yielded a PPXC film several cm in diameter with a thickness of 473 µm. This thickness was determined interferometrically by measuring the reflection spectrum of the film in the wavelength range 1440-1640 nm using a system developed to interrogate polymer film interferometers [9]. Due to interference in the film, its reflectivity exhibited a large number of spectral interference minima, the spacings between which were used to estimate the film thickness [14].
From the fabricated PPXC film, ten sub-films of lateral dimensions 9 mm ${\times} \; $ 40 mm were cut to fit snugly in an optical cuvette. Each of these new films was arbitrarily assigned a partner film, providing five labelled film pairs.
The above process was repeated once using fewer coating runs to produce five 219 µm films.
All the films were visually clear. However, some had surface defects resembling scratches, possibly an imprint of imperfections on the substrates.
3.2 Transmittance measurements
To measure the absorption coefficient of PPXC and the host liquid used in the cuvettes, we measured the wavelength-resolved transmittance of liquid-filled cuvettes with and without added PPXC films (Fig. 1). We also measured the transmittance of single PPXC films in air.
3.2.1 Spectrophotometer
A double-beam spectrophotometer (Lambda 750S, Perkin Elmer) was used to make transmittance measurements. In this spectrophotometer, broadband light is generated by a deuterium (UV) and a tungsten-halogen (VIS-NIR) lamp and spectrally filtered by a monochromator with a programmable slit width and central wavelength in the range 190-3300 nm. After filtering, the light is collimated and apertured to provide a beam with a rectangular spatial profile. This beam passes through a sample chamber in which it is weakly-focused on a pre-aligned cuvette holder. The beam is then steered into a detection module in which its intensity is measured. Two detection modules were used. One was a "standard" module in which light was detected by a photomultiplier tube (PMT; if λ < 860 nm) or a lead-sulphide detector (if λ > 860 nm). The other was a "sphere" module, in which light was detected by either a PMT (if λ < 860 nm) or an InGaAs detector (if λ > 860 nm), both housed in an integrating sphere, allowing the detection of light scattered through a sample into multiple directions.
The spectrophotometer has two optical paths, a "sample arm" and a "reference arm". In each of these arms, the beam travels a similar distance and encounters a similar sample chamber. The reference arm performs two roles. Firstly, it acts to reduce errors due to temporal changes in the sensitivity of the spectrophotometer, e.g., due to drifts in the lamp intensity. To minimize such errors, the spectrophotometer records the ratio of the light intensities measured near-simultaneously in the sample and reference arms. Secondly, to increase the SNR of its light intensity measurements, the spectrophotometer automatically tunes its sensitivity (detector gain and monochromator slit width) to match the light intensity available in the reference arm. In these conditions, the spectrophotometer can be optimized to detect the amount of light transmitted through the sample in the sample arm with high SNR if an object of similar transmittance is placed in the reference arm. When measuring the transmittance of a liquid-filled cuvette with added films for example, a suitable reference object could be a similar cuvette without added films. In the present study however, it was found that using the reference arm in this way had little impact on the uncertainty in our PPXC transmittance and absorption measurements. This was because this uncertainty was limited by systematic factors (e.g., cuvette surface cleanliness and uncertainty on the corrections), rather than the error on individually measured transmitted intensities. For this reason, reference cuvettes were used only in some and not all of the measurements, as indicated below.
3.2.2 Cuvettes
The optical cuvettes used in this study were made of fused silica (QX, Hellma Optics) or glass (OS, Hellma Optics), and had path lengths in the range 2-20 mm. The cuvette materials had known spectrally-resolved refractive indices, supplied by the manufacturer. Cuvettes were cleaned using isopropanol before each transmittance measurement.
3.2.3 Measurements
For a selected wavelength, the spectrophotometer measures the ratio of the transmitted light intensity measured in its sample arm, S, and in its reference arm, R. i.e., the measurement is:
(9)$$ {{M_{sample}} = \frac{S}{R} = \frac{{{P_{sa}}{T_s} + O}}{{{P_{ra}}{T_r} + O}},}$$
where: ${P_{sa}}$ and ${P_{ra}}$ are the sample-free transmittances of the sample and reference arms; ${T_s}$ and ${T_r}$ are the transmittances of objects positioned in the arms (the sample and reference materials); and O is a detector offset. To eliminate the unknowns in Eq. (9) and obtain the transmittance of the sample, ${T_s}$, two further measurements are needed in addition to ${M_{sample}}$. In the first, ${M_{open}} = ({{P_{sa}} + O} )/R$, the sample is removed such that ${T_s}$ becomes 100%. In the second, ${M_{dark}} = O/R$, the sample is replaced by a fully opaque object such that ${T_s}$ becomes zero. Note, if a reference material is used in the reference arm, this must be identical in all three measurements. ${T_s}$ can then be computed as:
(10)$$ {{T_s} = \frac{{{M_{sample}} - {M_{dark}}}}{{{M_{open}} - {M_{dark}}}}}$$
We pre-programmed the spectrophotometer to make a series of these measurements at different wavelengths in sequence with a chosen minimum and maximum wavelength, wavelength step, and spectral slit width. Samples were positioned either in the fixed, pre-aligned cuvette holder in the sample arm (in the case of 5-10 mm cuvettes), or directly in front of this holder (in the case of free-standing films or larger cuvettes). All measurements were recorded to a computer for offline processing. When measuring ${M_{dark}}$, the sample arm was blocked with an opaque aluminium block.
4.1 Host liquid characterization
Measuring absorption in PPXC films in liquid filled cuvettes required selecting a suitable host liquid in which to immerse the films. The principal requirement for the liquid was that its refractive index was known and well matched to that of PPXC in order to minimize (i) surface scattering due to any film imperfections and (ii) the Fresnel reflection coefficient at the film surface and thus reduce the magnitude of the errors associated with its calculation. A further requirement was that the liquid should be weakly absorbing. Based on these requirements, a commercial refractive index matching liquid (50350, Cargille Laboratories) was chosen to act as the host liquid. This liquid had a well-known refractive index, was sufficiently well matched to PPXC, and was sufficiently transparent (at many wavelengths) as discussed further below.
4.1.1 Refractive index
Quantifying the refractive index mismatch between the host liquid and PPXC required obtaining the index of both materials over the wavelength range of interest. The indices of both materials were also needed to calculate the total interfacial transmittances of samples and the liquid absorption coefficient, both of which were required for calculating the absorption coefficient of PPXC films.
Based on a literature review, it was found that the refractive index of PPXC in the plane of the film (PPXC is birefringent) is represented well by the Cauchy equation:
(11)$$ {{\textrm{n}_{\textrm{PPXC}}} = 1.618 + ({1.17 \times {{10}^{ - 2}}} )\; {\mathrm{\lambda }^{ - 2}},}$$
in which $\mathrm{\lambda }$ is the wavelength in micrometers. This equation is based on refractive index measurements at wavelengths in the range 400-1000 nm [20] and provides values consistent with other reported measurements in this wavelength range [1,3,5,7]. For the refractive index of the liquid, the manufacturer provided a Cauchy equation based on measurements in the wavelength range 225-1550 nm:
(12)$$ {{\textrm{n}_{\textrm{liquid}}} = 1.4469 + ({3.99 \times {{10}^{ - 3}}} )\; {\mathrm{\lambda }^{ - 2}} + ({3.76 \times {{10}^{ - 5}}} )\; {\mathrm{\lambda }^{ - 4}}.}$$
At wavelengths outside these ranges, refractive index data could not be found for either material so it was assumed that Eq. (11) and Eq. (12) remained valid for all other wavelengths in the 330-3300 nm range of interest. Using these equations, the refractive indices of PPXC and the liquid were calculated and plotted in Fig. 2 (left axis). Over the plotted wavelength range, the index of PPXC is in the range 1.62-1.72, while that of the liquid is in the range 1.44-1.49. The indices of the materials are therefore matched to within about 0.2. The Fresnel reflection coefficients for a PPXC-air interface and a PPXC-liquid interface were calculated and are also plotted in Fig. 2 (right axis). The coefficients for a PPXC-liquid interface are well below 1% and more than an order of magnitude lower than those for a PPXC-air interface. Consequently, low errors are expected when calculating the interfacial transmittances of PPXC films in this liquid and any residual surface scattering due to film imperfections is expected to be minimal.
Fig. 2. Refractive index of PPXC [20] (in the plane of the film) and host liquid (left axis, colored black), and Fresnel reflection coefficients of PPXC films in air and liquid (right axis, colored red). In the refractive index plots, solid lines indicate values within the wavelength ranges of the measurements from which the refractive index data were derived, while dashed lines indicate values outside these ranges.
4.1.2 Absorption coefficient
To measure the absorption coefficient of the liquid, we measured the transmittance of a cuvette filled with the liquid. To account for absorption in the cuvette walls, we also measured the transmittance of the same cuvette when empty. The internal transmittance of the liquid was obtained by computing the ratio of the liquid-filled and empty cuvette transmittances, after correcting for reflections. The absorption coefficient was calculated using Eq. (1).
To validate the method, we measured the absorption coefficient spectrum of water. Measurements were made using 2, 10, and 20 mm cuvettes and combined to produce a single absorption spectrum. The calculated spectrum is plotted in Fig. 3 along with the known absorption spectrum of water [21]. The data are in close agreement suggesting the method is valid. The same procedure was then applied to measure the absorption coefficient spectrum of the host liquid, which is also plotted in Fig. 3. In general terms, the absorption coefficient of the liquid increases with increasing wavelength, spanning a large range of values, from 0.001 mm-1 or lower to about 3 mm-1. The spectrum also exhibits a number of local peaks such as at 1720nm as marked on the plot (and referred to below in the following section). Absorption coefficients were also calculated using transmittance data provided by the liquid supplier at certain discrete wavelengths. These coefficients are in good agreement with the other measurements.
Fig. 3. Absorption coefficient spectra of the host liquid and deionized water. Measured absorption values are plotted along with liquid values calculated from the supplier's transmittance data and water measurements from literature [21]. The shaded regions show uncertainties (±1$\sigma $) based on the measurement error and the uncertainties associated with the reflection corrections.
4.2 PPXC absorption measurements
To obtain a first indication of the PPXC absorption spectrum, conventional transmittance measurements were performed using single PPXC films in air. Next, the method described in section 2 was applied to measure the absorption coefficient of PPXC using four PPXC films immersed in liquid. Finally, to provide additional confidence in the results, it was decided to repeat the measurements made in liquid using different numbers of films, different total film thicknesses, different cuvettes, and different detectors to see whether the results agreed.
4.2.1 PPXC absorption measurements using films in air and in liquid
The transmittances of individual 473 µm thick PPXC films were measured in air. The internal transmittance was obtained using Eq. (2), after estimating the Fresnel transmission coefficients of the film surfaces using Eq. (3). The absorption coefficient of the film was then calculated using Eq. (1). The measurements were made using a subset of the available PPXC films and repeated several times. No reference material was used in the reference arm of the spectrophotometer.
Measurements were then made using 473 µm thick films in liquid. The transmittance of a liquid-filled cuvette was measured with and without four added films. The internal transmittance and absorption coefficient of the films were calculated as described in section 2. These measurements were made using all ten possible combinations of two of the five available PPXC film pairs and repeated, yielding 20 independent measurements. A similar liquid-filled cuvette (without films) was used as a reference material in the reference arm of the spectrophotometer.
The internal transmittance and absorption coefficient spectra for PPXC films measured in air and in liquid are plotted in Fig. 4. The transmittance measurements in air (Fig. 4(a), grey line) show a broadband transmission window spanning almost the full wavelength range of the measurements. Within this window, there are a number of minima, for example at 1144 nm, 1384 nm, 2168 nm, and (several) around 2440 nm. The relative uncertainty is about 3% at most wavelengths, although this is higher at the spectral extremes of the measurements.
Fig. 4. (a) Internal transmittance and (b) absorption coefficient of single PPXC films in air and four PPXC films in liquid. These data are based on transmittance measurements using 473 µm thick PPXC films, a wavelength step of 4 nm, and a slit width of 1 nm (liquid) or 2 nm (air). The shaded regions show uncertainties (±1$\sigma $) based on the measurement error and the uncertainties associated with the host liquid absorption and interfacial reflection corrections. The arrow marked "D" indicates a known artefact related to the spectrophotometer switching between its two detectors. Other arrows highlight spectral features (in nm), as referred to in the main text. Measurements in liquid were limited to wavelengths <2250 nm because, at longer wavelengths, high absorption in the liquid (Fig. 3) prevented accurate measurements being made.
As expected from the internal transmittance spectrum, the absorption spectrum measured in air (Fig. 4(b), grey line) reveals a broad window with the highest absorption near the spectral limits of the measurement. The spectrum also contains absorption peaks corresponding to each of the measured transmittance minima. Compared to the uncertainties on the transmittance, the uncertainties on the absorption coefficients are significantly more variable. This is a consequence of the nonlinear propagation of the uncertainty in the transmittance via the logarithm operator in Eq. (1). This means that a given uncertainty in the transmittance maps to a higher uncertainty in the absorption coefficient when the transmittance is higher. Uncertainties in the absorption coefficients are therefore typically higher when the transmittance is high. For instance, in the wavelength range 550-1650 nm, where the transmittance is near 100%, the uncertainty in the absorption coefficient is one to several times the value of the absorption coefficient. By contrast, at wavelengths higher than 2120 nm, where the transmittance is <90%, the uncertainty in the absorption coefficient is lower (in the range 3-33%).
The internal transmittance of PPXC measured using four films in liquid (Fig. 4(a), blue line) is lower than the transmittance measured using one film in air, as expected due to the larger total thickness of PPXC. At most wavelengths <1670 nm, the uncertainties are typically about 1.5%, i.e., about half those seen in air. These lower uncertainties are likely a consequence of the reduced surface scattering and lower interfacial reflections when the films are in the liquid. At longer wavelengths, the uncertainties are higher and more variable, and higher than those seen in air. For example, they are >30% at wavelengths in the range 1690-1780nm, and in the range 2-20% at 1800-2200 nm. These higher uncertainties are a result of high light absorption in the host liquid (Fig. 3) leading to a lower transmittance through the samples and therefore lower accuracy. In the most extreme cases, prohibitively high liquid absorption led to transmittance being effectively unmeasurable. This occurred both near to 1720nm, where the absorption coefficient of the host liquid peaks locally (Fig. 3), and at wavelengths >2250 nm. To highlight these spectral bands, they are labelled "regions of high liquid absorption" in Fig. 4.
The absorption spectrum calculated from the measurements made in the liquid (Fig. 4(b), blue line) agrees with the spectrum calculated from the measurements made in air. However, the uncertainties are typically significantly lower. For example, at wavelengths below 1670 nm, the uncertainties are in the range 1-30% and about an order of magnitude lower than those obtained in air. This is mainly due to the nonlinear mapping of transmittance to absorption described above. In other words, decreasing the transmittance by extending the path length in PPXC by using multiple films reduced the uncertainty on the absorption coefficient. To a lesser degree, the lower uncertainties are also a consequence of the reduced surface scattering and lower Fresnel reflection coefficients that arise when the films are in the liquid. The exception is at wavelengths where the host liquid absorption was prohibitively high. For these wavelengths, absorption data is not plotted because it was obviously erroneous. Fortunately, in these spectral bands (marked "regions of high liquid absorption" in Fig. 4), the absorption coefficient of PPXC was found to be sufficiently high that the measurements in air were highly accurate. Thus, between them, the air and liquid based methods provided accurate absorption measurements across the majority of the studied spectral range (see section 4.2.3).
4.2.2 Measurements using multiple film thicknesses, different numbers of films, different liquid path lengths, different cuvette materials, and different detectors
To provide additional confidence in the measured PPXC absorption coefficients, it was decided to repeat the measurements using different numbers of films, different total film thicknesses, a different cuvette made of a different material and with a shorter path length, and different detectors to see if the results agreed.
First, the PPXC measurements performed in liquid (Fig. 4) were repeated using two, six and ten films. The resulting transmittance spectra are plotted in Fig. 5(a), along with the original one and four film data. As expected, the transmittance decreased as the number of films increased, due to the increasing path length in PPXC. To verify that this reducing transmittance followed an exponential decay with increasing path length as expected from Eq. (1), the transmittance was plotted as a function of the path length in PPXC for selected wavelengths in Fig. 5(b), with exponential functions fitted to the data. These provided a good fit and the exponential constants were consistent with the absorption coefficients obtained in the original measurements.
Fig. 5. PPXC internal transmittance and absorption coefficient spectra obtained using different numbers of films, different cuvettes and different detectors. (a) Internal transmittance measured using 1, 2, 4, 6 and 10 PPXC films. For 1 film and 4 films, the data is the same as the data plotted in Fig. 4. For 2, 6 and 10 films, measurements were made in liquid. (b) Internal transmittance as a function of path length in PPXC at selected wavelengths, sampled from the transmittance plots in (a). (c) PPXC absorption coefficient spectra obtained using different numbers of films, different cuvettes, films of different thickness, and two different detectors (one standard detector and one integrating sphere based detector). In (a) and (c), the wavelength range is limited to <2200 nm because measurements in liquid were inaccurate due to high liquid absorption at longer wavelengths (Fig. 3). To de-clutter the graph, uncertainties are omitted except in the original 4 film data and datasets were down-sampled to limit the number of plotted points. "D" marks the detector step artefact described in the caption of Fig. 4.
Next, to test the robustness of the measurements to parameters other than the number of films, the measurements in liquid were repeated in other conditions. Firstly, the measurements were repeated using a different cuvette made from glass instead of fused silica and with a path length of 5 mm instead of 10 mm. Secondly, the measurements were repeated using a different number of independently fabricated PPXC films with a lower thickness of 219 µm. Finally, the measurements were repeated using an integrating sphere detector to provide a preliminary verification that the films were non scattering (see discussion). The resulting absorption coefficient spectra are plotted in Fig. 5(c). All the spectra are in good agreement with the spectrum originally obtained in liquid.
4.2.3 PPXC absorption spectrum
The accuracies of the absorption measurements made in liquid and air were found to be wavelength dependent. The liquid measurements provided high accuracy over most of the spectral range but there were certain wavelength ranges in which the accuracy was poor due to the high absorption of the liquid. Fortunately, these wavelength ranges coincided with those in which PPXC absorption was so high that the single film measurements made in air provided acceptable accuracy. It was therefore possible to obtain an accurate absorption spectrum over almost the entire 330-3300 nm range by combining the measurements made using both methods. The measurements were combined in three steps. Firstly, all the absorption values were taken from the spectrum obtained using four films in liquid (Fig. 4). Secondly, the values were replaced by those obtained using a narrower cuvette (Fig. 5) where this provided a reduced uncertainty. This occurred when the liquid absorption coefficient was high enough to limit the accuracy in 10 mm cuvettes, but not so high as to prevent accurate measurements using the 5 mm cuvette. Thirdly, the values were replaced with those obtained using films in air (Fig. 4) where this provided a reduced uncertainty. This occurred in spectral regions where the liquid absorption was so high as to prevent accurate measurements being made through either cuvette. The resulting spectrum is plotted in Fig. 6.
Fig. 6. PPXC absorption spectrum obtained by combining multiple datasets to provide high accuracy over the whole plotted wavelength range. The arrow labelled "D" indicates the detector step. The inset shows a zoomed in version of the plot of the absorption coefficient in the wavelength range 1410-1640 nm. Light with a wavelength in this range is commonly used in PPXC based optical sensors [9] and in optical telecommunications (note: there is a linear Y axis scale on the inset only). For convenience, the right-hand Y-axis presents the measured absorption as an equivalent transmission loss in units of dB/cm. This is defined as $10 \times {\log _{10}}({T_{1\textrm{cm}}}),\; $ where ${T_{1\textrm{cm}}} = {e^{ - ({{\mu_a}\; \times \; 1\textrm{cm}} )}}$ and represents the fractional power transmitted over a path length of 1 cm in PPXC. The data underlying this figure is available in Dataset 1 [22].
The spectrum shows the PPXC absorption coefficient over the wavelength range 330-3300 nm. At 330 nm, the absorption coefficient is 4.3 mm-1. This decreases smoothly with increasing wavelength, by about 2 orders of magnitude to about 0.05 mm-1 at 860 nm. Between 860 nm and 1562 nm, the absorption coefficient decreases gradually except for peaks near to 1170 nm and 1410 nm. At 1562 nm, the coefficient reaches a minimum value of 0.025 mm-1. Above 1562 nm, the coefficient increases sharply to about 0.4 mm-1 at 1680 nm. At 1800-2100 nm, the coefficient flattens at about 0.12 mm-1. At 2170-2700 nm, there are a number of peaks with maximal values in the range 0.8-1.8 mm-1. At 2750-3000 nm, the coefficient flattens again at about 0.4 mm-1. The coefficient then increases relatively steadily to 7.7 mm-1 at 3262 nm. At longer wavelengths, the coefficient was unmeasurable in our experiments because the light intensity transmitted through the sample was too low, even for a single film in air.
The visible and near infrared absorption coefficient spectrum of PPXC was obtained by measuring the transmittance of single PPXC films in air and multiple films in liquid. The measured absorption coefficients ranged from 0.025 mm-1 to 7.7 mm-1 (Fig. 6), equivalent to intensity transmission losses in the range 1-350 dB/cm. For context, at wavelengths ≤850 nm, the measured absorption coefficient is at least an order of magnitude higher than that of PMMA [23]. At other wavelengths, near 1500 nm for example, the absorption coefficient is similar to that of PMMA [23]. The mean estimated uncertainty on the PPXC absorption coefficient was ±16%. Repeat measurements made using different film thicknesses, different numbers of films, different cuvettes, and different detectors yielded values in mutual agreement, suggesting the measurements were accurate.
The measurements are broadly consistent with the limited PPXC absorption data available in the literature. For example, the relative PPXC transmittance spectrum reported by Jeong et al. [3] (from which it is not possible to extract absorption coefficients because the film thickness is unknown) showed that the transmittance increased smoothly to a plateau with increasing wavelength in the range 330-1000 nm. This is consistent with the trends seen in the transmittance spectra measured in this study such as those in Fig. 4(a). Likewise, the absorbance spectrum recorded by Bera et al. [15] (prior to exposing PPXC films to UV light) showed a similar trend in the form of a decreasing absorbance with increasing wavelength in the range 300-500 nm. Moreover, as the film thickness was reported, absorption coefficients can be calculated from this data (e.g., 8.2 mm-1 at 330 nm, 3.6 mm-1 at 400 nm, and 1.4 mm-1 at 500 nm). These coefficients are 2-5 times higher than those measured in the present study (4.3 mm-1 at 330 nm, 0.86 mm-1 at 400 nm, and 0.28 mm-1 at 500 nm). However, this may be because Fresnel reflections were not accounted for by Bera et al. [15]. To test this hypothesis, we converted their absorbance into transmittance using the film thickness, then divided out the expected losses due to Fresnel reflections assuming two PPXC-air interfaces. After this correction, the calculated coefficients agreed with those measured in the present study within 0-15% at wavelengths below 395 nm. With increasing wavelength, they tended towards zero, leading to decreasing agreement. However, this could be attributed to the decreasing accuracy with increasing wavelength expected in the literature measurements due to the low PPXC film thickness (46 µm), coupled with the fact PPXC becomes increasingly transparent in this wavelength range. Of the studies reporting losses measured at single wavelengths, Xie et al. [8] reported an absorption coefficient of 0.17 mm-1 using a ≈470 nm LED source. This is about two times smaller than the value measured in this study (0.37 mm-1) at 470 nm. Reddy et al. [6] reported waveguides losses equivalent to absorption coefficients of 0.14 mm-1 at 450 nm, 0.11 mm-1 at 532 nm, 0.09 mm-1 at 633 nm, 0.08 mm-1 at 680 nm. These values are 2-3 times lower than ours at 450 and 532 nm but in agreement at 633 nm and 680 nm. Overall, the fact that previously published relative spectra are broadly consistent with the measurements made here, and the few absolute absorption coefficients reported at specific wavelengths agree, at worst, within a factor of 2-3, is encouraging given the limitations of the previous studies.
In this study, measurements were made using a total of fifteen different films, drawn from two independently fabricated master films of thickness 473 µm and 219 µm. Because only two sets of independently fabricated films were used, it was not possible to rigorously investigate the impact of variability between PPXC fabrication runs, or differences in absorption that might be caused by changing the fabrication protocol. A good agreement was found, however, between the measurements obtained using the two sets of independently fabricated films. Repeat measurements made over a time period of about 18 months also agreed. The measurements therefore accurately represent PPXC films made on at least two separate occasions, films of at least two thicknesses, and films before and after lab storage over a period of up to 18 months. Although the measurements involving these films were consistent, certain fabrication parameters and environmental factors are known to affect PPXC properties including the visual appearance of films. For example, the sublimation temperature affects the film crystallinity [24] and UV light can induce yellowing [15,25], which is reflected in a change in absorbance [15]. Further studies could investigate the impact of deposition parameters, UV exposure, inter-lab variability, or other factors by applying the presented method to measure the absorption coefficient of a larger variety of PPXC films fabricated and stored differently.
To calculate PPXC absorption coefficients from the measurements made in liquid, certain assumptions were made. One assumption was that the optical thickness of the PPXC film was not changed due to the immersion of the film in the liquid. In fact, although PPXC is commonly considered an excellent chemical barrier, it has been observed to swell in certain liquids [26,27]. For films of comparable thickness to ours, the swelling has been reported as up to a few percent after tens of hours of immersion [26]. To our knowledge, this effect has not been studied in the liquid used in this study. However, even if we assume similar swelling in this liquid, as the samples were immersed for a much shorter time, any associated thickness errors would be expected to be significantly lower than a few percent. This would propagate to a negligibly small error on the absorption coefficient, suggesting this effect could be safely neglected. A second assumption involved the Cauchy equations used to provide the refractive indices of PPXC and the liquid (Fig. 2). These were known to be valid at certain wavelengths, namely 400-1000 nm for PPXC and 225-1550 nm for the liquid. However, they were also assumed to be valid at other wavelengths, at which the indices were unknown. At wavelengths below 2200 nm, there is evidence that the assumption was accurate in that the absorption measurements made in air and in liquid agreed (Fig. 5). At longer wavelengths however, the validity remains uncertain. At these wavelengths, the validity of the liquid index is unimportant because the measurements in liquid were unsuccessful due to the high liquid absorption at these wavelengths. However, any inaccuracies in the PPXC index at these wavelengths would lead to errors in the reflection corrections and subsequently in the calculated PPXC absorption coefficient. As such, the PPXC absorption coefficients measured at wavelengths <2200 nm should be treated with greater confidence than those measured at longer wavelengths.
A final question is whether the measured spectrum represents PPXC absorption only, or if it might also include losses due to scattering inside the material. Throughout this manuscript, it was assumed that absorption is the dominant process and internal scattering is negligible. Consistent with this assumption, the measurements made using an integrating sphere to capture light scattered by the sample agreed with the original measurements in which only unscattered light was detected (Fig. 5). Although this might suggest scattering was negligible, the sample was positioned approximately 30 cm from the sphere, rather than immediately next to it. As such, the solid angle subtended by the sphere was small and the sphere may therefore not have been able to capture enough of any scattered light to firmly conclude that there was no internal scattering. The presence of scattering could be studied more comprehensively by adapting the apparatus to place the sample immediately next to the sphere to capture more of any scattered light.
The visible and near infrared absorption coefficient spectrum of PPXC was measured using a combination of conventional PPXC film transmittance measurements and a method involving immersing multiple films in a liquid to increase sensitivity. The coefficient was found to be in the range 0.025 mm-1 to 7.7 mm-1, equivalent to transmission losses of about 1-350 dB/cm, in the wavelength range 330-3262 nm. Confidence in the accuracy of these measurements is underscored by the consistency in the data acquired under different conditions and from multiple independent repeat experiments. In addition, where the measurements can be compared to the few limited studies in the literature, they are broadly consistent.
The PPXC absorption coefficient spectrum could be useful when designing PPXC based optical devices such as sensors and waveguides. For instance, when designing PPXC-based optical ultrasound sensors for photoacoustic imaging [9], the absorption coefficients could be included in optical models of the sensors, allowing a more accurate calculation of the expected sensor sensitivity [28]. This could aid the design of new sensors by enabling the selection of parameters such as optimal mirror reflectivities and spacer thicknesses that minimise the deleterious impact of PPXC absorption. Accurate knowledge of the PPXC absorption coefficient could also be helpful when designing PPXC waveguides to be used for optogenetics [5,8]. At wavelengths in the range 470-532 nm [5,8] for example, the measured absorption coefficient indicates a maximum $1/e$ transmission length of 3-5 mm in PPXC. This, and similar calculations, could provide an indication of the maximum permissible length for a PPXC waveguide required to deliver a given light intensity in order to elicit neuronal activation.
Beyond PPXC, the method of immersing multiple films in liquid provides a new way to measure the absorption coefficient of low-loss materials. The fundamental advantage is this provides increased sensitivity without requiring a physically thicker sample. The method also limits errors related to surface scattering and Fresnel reflections. Having described the theoretical basis and demonstrated the feasibility of this method, it could now be used to study the attenuance of other materials, especially other low-loss materials for which it is equally difficult to obtain thick samples. For example, the method could be applied to study other polymers in the Parylene family [1] such as fluorinated variants which might afford lower absorption [29–31]. Quantifying lower absorption coefficients in such materials could lead to the development of thin film optical devices with enhanced performance such as more sensitive optical ultrasound sensors and more efficient waveguides.
Royal Society (URF\R1\180435); European Research Council (741149); Engineering and Physical Sciences Research Council (EP/L016478/1); Engineering and Physical Sciences Research Council (NS/A000050/1).
The authors acknowledge Christian Sol for useful conversations concerning the refractive index of Parylene C and ellipsometry measurements.
The authors do not declare any financial interests or conflicts of interest.
The PPXC absorption spectrum in Fig. 6 is available online in Dataset 1 [22]. Other data are not publicly available at this time but may be obtained from the authors upon reasonable request.
1. W. F. Beach, "Xylylene polymers," Encyclopedia of Polymer Science and Technology 12, 587–626 (2002).
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23. R. C. Progelhof, J. Franey, and T. W. Haas, "Absorption coefficient of unpigmented poly(methyl methacrylate), polystyrene, polycarbonate, and poly(4-methylpentene-1) sheets," J. Appl. Pol 15(7) 1803–1807 (1971). [CrossRef]
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30. A. Kahouli, A. Sylvestre, F. Jomni, E. André, J. L. Garden, B. Yangui, B. Berge, and J. Legrand, "Dielectric properties of parylene AF4 as low-k material for microelectronic applications," Thin Solid Films 520(7), 2493–2497 (2012). [CrossRef]
31. W. R. Dolbier and W. F. Beach, "Parylene-AF4: A polymer with exceptional dielectric and thermal properties," Journal of Fluorine Chemistry 122(1), 97–104 (2003). [CrossRef]
W. F. Beach, "Xylylene polymers," Encyclopedia of Polymer Science and Technology 12, 587–626 (2002).
B. J. Kim and E. Meng, "Micromachining of Parylene C for bioMEMS," Polym. Adv. Technol. 27(5), 564–576 (2016).
Y. S. Jeong, B. Ratier, A. Moliton, and L. Guyard, "UV-visible and infrared characterization of poly(p-xylylene) films for waveguide applications and OLED encapsulation," Synth. Met. 127(1-3), 189–193 (2002).
S. Yamagiwa, M. Ishida, T. Kawano, S. Yamagiwa, M. Ishida, and T. Kawano, "Flexible parylene-film optical waveguide arrays," Appl. Phys. Lett. 083502(2015), 1–6 (2016).
J. W. Reddy and M. Chamanzar, "Low-loss flexible Parylene photonic waveguides for optical implants," Opt. Lett. 43(17), 4112 (2018).
J. W. Reddy, M. Lassiter, and M. Chamanzar, "Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces," Microsyst Nanoeng 6(1), 85 (2020).
O. I. Szentesi and E. A. Noga, "Parylene C films for optical waveguides," Appl. Opt. 13(11), 2458–2459 (1974).
T. Xie, X. Bi, R. Luo, F. Bin, Z. Wang, and W. Li, "Optical propagation of blue LED light in brain tissue and Parylene-C," 2017 IEEE 12th Int. Conf. Nano/Micro Eng. Mol. Syst. NEMS 2017, vol. 2 (2017), 599–602.
E. Zhang, J. Laufer, and P. Beard, "Backward-mode multiwavelength photoacoustic scanner using a planar Fabry-Perot polymer film ultrasound sensor for high-resolution three-dimensional imaging of biological tissues," Appl. Opt. 47(4), 561–577 (2008).
J. Buchmann, J.A. Guggenheim, E. Z. Zhang, C. Scharfenorth, B. Spannekrebs, C. Villringer, and J. Laufer, "Characterization and modeling of Fabry–Perot ultrasound sensors with hard dielectric mirrors for photoacoustic imaging," Appl. Opt. 56(17), 5039 (2017).
P. Hajireza, K. Krause, M. Brett, and R. Zemp, "Glancing angle deposited nanostructured film Fabry-Perot etalons for optical detection of ultrasound," Opt. Express 21(5), 6391 (2013).
P. Morris, A. Hurrell, A. Shaw, E. Zhang, and P. Beard, "A Fabry-Perot fiber-optic ultrasonic hydrophone for the simultaneous measurement of temperature and acoustic pressure," J. Acoust. Soc. Am. 125(6), 3611–3622 (2009).
S. Dufour and Y. De Koninck, "Optrodes for combined optogenetics and electrophysiology in live animals," Neurophotonics 2(3), 031205 (2015).
J. A. Guggenheim, J. Li, T. J. Allen, R. J. Colchester, S. Noimark, O. O. Ogunlade, I. P. Parkin, I. Papakonstantinou, A. E. Desjardins, E. Z. Zhang, and P. C. Beard, "Ultrasensitive plano-concave optical microresonators for ultrasound sensing," Nat. Photonics 11(11), 714–719 (2017).
M. Bera, A. Rivaton, C. Gandon, and J. L. Gardette, "Comparison of the photodegradation of parylene C and parylene N," Eur. Polym. J. 36(9), 1765–1777 (2000).
G. Gauglitz and T. Vo-Dinh, Handbook of SpectroscopyWiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG (2003).
A. Hordvik, "Measurement techniques for small absorption coefficients: recent advances," Appl. Opt. 16(11), 2827 (1977).
A. V. Khomchenko, "Waveguide spectroscopy of thin films," Tech. Phys. Lett. 27(4), 271–274 (2001).
W. Heitmann, "Attenuation measurement in glasses for optical communications: an immersion method," Appl. Opt. 15(1), 256 (1976).
J. F. Gaynor and S. B. Desu, "Optical properties of polymeric thin films grown by chemical vapor deposition," J. Mater. Res. 11(1), 236–242 (1996).
G. M. Hale and M. R. Querry, "Optical Constants of Water in the 200-nm to 200-Mm Wavelength Region," Appl. Opt. 12(3), 555–563 (1973).
J. A. Guggenheim, Y. Lyu, D. M. Marques, E. Z. Zhang, and P. C. Beard, "Parylene C absorption coefficient spectrum," figshare, (2021). https://doi.org/10.6084/m9.figshare.14564550.
R. C. Progelhof, J. Franey, and T. W. Haas, "Absorption coefficient of unpigmented poly(methyl methacrylate), polystyrene, polycarbonate, and poly(4-methylpentene-1) sheets," J. Appl. Pol 15(7) 1803–1807 (1971).
G. Surendran, M. Gazicki, W. J. James, and H. Yasuda, "Polymerization of para-xylylene derivatives. V. Effects of the sublimation rate of di-p-xylylene on the crystallinity of parylene C deposited at different temperatures," J. Polym. Sci. Part A Polym. Chem. 25(8), 2089–2106 (1987).
G. Maggioni, A. Tessarollo, and S. Carturan, "Study of the effects of incorporation of UV-absorbing compound in parylene C films," Mater. Chem. Phys. 149, 530–538 (2015).
E. Miller and E. Leighton, "Swelling of Parylene C," J. Elastomers Plast. 22(1), 46–57 (1990).
H. C. Koydemir, H. Külah, and C. Özgen, "Solvent compatibility of parylene c film Layer," J. Microelectromech. Syst. 23(2), 298–307 (2014).
D. M. Marques, J. A. Guggenheim, R. Ansari, E. Z. Zhang, P. C. Beard, and P. R. T. Munro, "Modelling Fabry-Pérot etalons illuminated by focussed beams," Opt. Express 28(5), 7691 (2020).
A. Kahouli, A. Sylvestre, J. F. Laithier, L. Lutsen, S. Pairis, E. André, and J. L. Garden, "Structural and dielectric properties of parylene-VT4 thin films," Mater. Chem. Phys. 143(3), 908–914 (2014).
A. Kahouli, A. Sylvestre, F. Jomni, E. André, J. L. Garden, B. Yangui, B. Berge, and J. Legrand, "Dielectric properties of parylene AF4 as low-k material for microelectronic applications," Thin Solid Films 520(7), 2493–2497 (2012).
W. R. Dolbier and W. F. Beach, "Parylene-AF4: A polymer with exceptional dielectric and thermal properties," Journal of Fluorine Chemistry 122(1), 97–104 (2003).
Allen, T. J.
André, E.
Ansari, R.
Beach, W. F.
Beard, P.
Beard, P. C.
Bera, M.
Berge, B.
Bi, X.
Bin, F.
Brett, M.
Buchmann, J.
Carturan, S.
Chamanzar, M.
Colchester, R. J.
De Koninck, Y.
Desjardins, A. E.
Desu, S. B.
Dolbier, W. R.
Dufour, S.
Franey, J.
Gandon, C.
Garden, J. L.
Gardette, J. L.
Gauglitz, G.
Gaynor, J. F.
Gazicki, M.
Guggenheim, J. A.
Guggenheim, J.A.
Guyard, L.
Haas, T. W.
Hajireza, P.
Hale, G. M.
Heitmann, W.
Hordvik, A.
Hurrell, A.
Ishida, M.
James, W. J.
Jeong, Y. S.
Jomni, F.
Kahouli, A.
Kawano, T.
Khomchenko, A. V.
Kim, B. J.
Koydemir, H. C.
Krause, K.
Külah, H.
Laithier, J. F.
Lassiter, M.
Laufer, J.
Legrand, J.
Leighton, E.
Luo, R.
Lutsen, L.
Maggioni, G.
Marques, D. M.
Meng, E.
Miller, E.
Moliton, A.
Morris, P.
Munro, P. R. T.
Noga, E. A.
Noimark, S.
Ogunlade, O. O.
Özgen, C.
Pairis, S.
Papakonstantinou, I.
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Xie, T.
Yamagiwa, S.
Yangui, B.
Yasuda, H.
Zemp, R.
Zhang, E.
Zhang, E. Z.
Appl. Phys. Lett. (1)
Encyclopedia of Polymer Science and Technology (1)
Eur. Polym. J. (1)
J. Acoust. Soc. Am. (1)
J. Appl. Pol (1)
J. Elastomers Plast. (1)
J. Mater. Res. (1)
J. Microelectromech. Syst. (1)
J. Polym. Sci. Part A Polym. Chem. (1)
Journal of Fluorine Chemistry (1)
Mater. Chem. Phys. (2)
Microsyst Nanoeng (1)
Neurophotonics (1)
Polym. Adv. Technol. (1)
Synth. Met. (1)
Tech. Phys. Lett. (1)
Thin Solid Films (1)
Dataset 1 Optical absorption coefficient spectrum of Parylene C
(1) μ = − log  τ d ,
(2) T f = τ f F air → film 2 ,
(3) F 1 → 2 = ( 4 n 1 n 2 ( n 1 + n 2 ) 2 ) ,
(4) T m = τ c τ f e − μ l ( L − D ) F air → cuvette 2 F cuvette → liquid 2 F film → liquid m ,
(5) T 0 = τ c e − μ l L F air → cuvette 2 F cuvette → liquid 2 ,
(6) T 0 T m = e − μ l D τ f F film → liquid m ,
(7) τ f = T m T 0 C ,
(8) C = e − μ l D F film → liquid m
(9) M s a m p l e = S R = P s a T s + O P r a T r + O ,
(10) T s = M s a m p l e − M d a r k M o p e n − M d a r k
(11) n PPXC = 1.618 + ( 1.17 × 10 − 2 ) λ − 2 ,
(12) n liquid = 1.4469 + ( 3.99 × 10 − 3 ) λ − 2 + ( 3.76 × 10 − 5 ) λ − 4 .


Protection while you trailer, easier unloading when you have arrived. Protects your snowmobiles, ATV's and motorcycles from road grime, rocks and salt while hauling. Universal design fits most open trailers. 30" tall. Aerodynamic design to help with gas mileage. Our new LowPro Grip Glides are installed on the ramp to make unloading your snowmobile and ATV simple. Molded Grips down the center to give your snowmobile track traction. Protective gate to keep your ski away from the bumper of your tow vehicle. Lightweight HDPE guaranteed not to crack, chip, break or wear out. Stainless steel hardware included.


Do you think the U.S. economy can sustain the progress in its jobs market?
Of course! Businesses are booming and they're likely to ramp up hiring.
I doubt it. The oil industry is likely to report some job cuts sooner or later.
It depends on how the global economy fares in the coming months.


text:
Anti-masker 'Karens' abuse Ikea staff at Sydney store
Two anti-masker 'Karens' have hurled abuse at staff in a Sydney Ikea store, telling them to "shut up" after being asked to wear face masks.
Candace Suttoncandacesutton1
news.com.auJanuary 7, 202112:32am
Ikea 'Karens' abuse staff after being told to wear masks four times and refusing...
Ikea 'Karens' abuse staff after being told to wear masks four times and refusing
Two rude women verbally abused Ikea workers who asked them to wear masks in a Sydney store. Picture: Reddit/@7thwardcharizard1Source:Supplied
Two women have hurled abuse at staff in a Sydney Ikea store, telling them to "shut up" after being challenged for a fourth time for refusing to wear face masks while shopping.
One of the anti-maskers filmed a video of two Ikea workers at a checkout as both women stridently objected to being challenged about masks.
The video was posted on Reddit by user @7thwardcharizard1 on Tuesday, just three days after the NSW Government mandated mask wearing in shops and on public transport in response to new coronavirus clusters.
The footage is captioned, "And it begins … the idiots are out in full force! I don't know why I thought we in Sydney were better than this".
Non-mask wearers risk on-the-spot $200 fines, although only police officers can issue them, and children under 12 and people with certain medical conditions are exempt.
The two anti-masker women rudely insist to the male and female Ikea workers, who are dressed in uniform and both wearing face masks, that they are exempt adults.
One of the women starts filming the dispute after the pair clearly has been told again to wear a mask and tells the Ikea workers, "Shut. Up. It's the fourth time today".
The second woman says, "Yes it is … you know people have medical conditions, they have trauma, rape, abuse.
"They have a multitude of reasons as to why they are exempt. It is part of the law. It is unnecessary, it is unnecessary to act this way."
The female Ikea worker turns her back to the women and her male colleague steps forward to speak with the women, saying "you don't need to film her".
Two women stridently objected to being told to wear masks and abused the Ikea workers. Picture: Reddit/@7thwardcharizard1Source:Supplied
The women abused the Ikea workers and complained they'd been told four times to wear masks. Picture: Reddit/@7thwardcharizard1Source:Supplied
One of the anti-maskers objects, saying in a shrill voice, "I'm allowed to film her. It's my right to film her.
"You need to understand. In your website … your website says we are exempt."
The other woman says "If I'm not wearing a mask, there is a reason. The website says …"
But the male worker interrupts, saying "That's fine" and the woman snaps, "Shush, don't cut me off.
"The website says if you cannot wear a mask, you don't have to.
"'Clearly I'm not wearing it for a reason."
The other woman interjects, "Clearly you need to be informed of your own website. So you need to stop telling people to wear masks if they choose not.
"End of. Shush."
One of the women can then be briefly seen raising her hand up to the man, who tells her, "It's just what we've been told."
RELATED: Vegan influencer's Tik Tok video of G-string 'Karen'
RELATED: Balmain 'Karen' threatens fisherman with police
Reddit comments supported the workers. Picture: Reddit/@7thwardcharizard1Source:Supplied
The Ikea workers asked the women to wear masks. Picture: Reddit/@7thwardcharizard1Source:Supplied
One of the women then accuses the Ikea workers of "harassment" and tells them to "back off".
The video has attracted more that 300 comments on Reddit, most sympathetic with the Ikea staffers.
"I think if someone had a legitimate exemption and quietly told the manager there would be no issue," one person posted, "These entitled f***ers were looking for a fight."
"The people working at the shops are just doing their jobs and following the new rules. These ladies are just acting entitled," another wrote.
"I feel so bad for the workers that have to deal with this s**t now," another said.
"Putting others at risk and rattling on about abuse victims whilst they verbally abuse innocent people just doing their job. Disgusting," wrote another.
The video is reminiscent of those filmed of "Bunnings Karen" and others in the days after Melbourne mandated masks on July 22 last year.
In Sydney, noisy protesters took to the streets of Bondi Junction and paraded through a shopping centre on Sunday, a day after the mask rule began but still while there was a grace period for fine imposition.
Masks are mandated indoors in Great Sydney, Wollongong, the Central Coast and the Blue Mountains in shops, businesses and on buses, trains, and in taxis and ride share vehicles.
candace.sutton@news.com.au

redpajama_set_name: RedPajamaCommonCrawl


text:
A Favorite Ice Cream And A New Movie Share A Name
Riverside, California (NAPSI) - Here's a cool scoop. If you are looking for a way to celebrate National Ice Cream Month which is July and chill out on National Ice Cream Day in particular, which happens to be this Sunday, why not give some love to that all-American favorite, Rocky Road?
A Favorite Flavor
The flavor was created in 1929 by William Dreyer in Oakland, California when he cut up walnuts and marshmallows with his wife's sewing scissors and added them to his chocolate ice cream in a manner that reflected his partner Joseph Edy's chocolate candy creation, incorporating walnuts and marshmallow pieces.
After the Wall Street Crash of 1929, Dreyer and Edy gave the flavor its current name "to give folks something to smile about in the midst of the Great Depression."
Typical ingredients today—chocolate, almonds (originally used walnuts) and marshmallows.
According to a recent survey by Behavioral Food Expert Juliet A. Boghossian and Baskin-Robbins, Rocky Road ranks 4th among the top 10 ice cream flavors that make people the happiest.
A New Feel-Good Movie
You can continue your celebration of National Ice Cream Day by sitting back with a scoop or two of Rocky Road and enjoying a sweet summer movie of the same name.
Rocky Road is a heartwarming, timely story about Harrison Burke, an out-of-luck Wall Street investment banker who finds himself back at home and working for his dad's ice cream truck business.
This UP television network original movie stars actor/singer-songwriter Mark Salling (Harrison), best known for his work in the hit show Glee, in his first leading-man role. Plus, Salling and Mark Miller wrote and performed an original song for the film entitled Back At the Starting Line (watch it at www.UPtv.com/RockyRoad).
The ensemble cast also includes Nicholas Campbell (Haven, A Heartland Christmas) and Deborah Tennant (Haven, Copper) as Harrison's parents Ben and Marla who are surprised and thrilled, but suspicious about his return home; sidekick and fellow route driver Jahmil French (Degrassi: The Next Generation) as Razor; and Rebecca Dalton (Spun Out, The L.A. Complex) as his old girlfriend Suzie Barnes. The film is directed by Emmy® Award winner Brian K. Roberts (Everybody Loves Raymond). Tippi and Neal Dobrofsky (Window Wonderland, Guess Who's Coming to Christmas) wrote the script.
UP is the television network dedicated to uplifting viewers every day with original movies, reality, drama and comedy series and music specials.
"We're happy to present Rocky Road on July 20th, as America celebrates a great American summer treat with National Ice Cream Day," said Sophia Kelley, senior vice president of programming, UP. "Like this enduring flavor of ice cream—celebrating its 85th birthday in 2014--this film showcases the strength of Mark Salling's character, Harrison, as he finds a simpler, sweeter life at home by returning to his family's ice cream truck business to help his dad through a sticky situation."
Rocky Road premieres on Sunday, July 20 at 8 p.m. ET and 7 p.m. PT. Check your local listings.
To learn more, visit www.UPtv.com/RockyRoad.


It is the sweltering summer of 1997, and Karen is a strait-laced, straight-A university student. When she meets the impossibly glamorous Biba, a bohemian orphan who lives in a crumbling old mansion in Highgate with her enigmatic brother Rex, she is soon drawn into their world - but something terrible is about to happen, and someone's going to end up dead..
Already drawing comparisons to Barbara Vine, Tana French and Sophie Hannah, Erin Kelly is an extraordinarily talented new author.


text:
Q: How to use createPattern from Context2D QML I want to use
variant createPattern(Image image, string repetition), but I don't know how to pass the image parameter. I tried to pass the id of an Image but the function returns an empty object.
variant createPattern(color color, enumeration patternMode) works like a charm.

A: As @folibis said, the source of
  createPattern should be an url.
For anyone looking for an example, here it is:
Canvas {
    id:canvas
    anchors.fill: parent
    onPaint:{
        var ctx = canvas.getContext('2d');
        var pattern = ctx.createPattern("file:///path_to_my_image.ext", 'repeat');
        ctx.fillStyle = pattern;
        ctx.fillRect(0, 0, canvas.width, canvas.height);
    }
  Component.onCompleted: canvas.requestPaint();
}

redpajama_set_name: RedPajamaStackExchange


text:
ROWDY BURNS PICKS PERFECT TIME FOR WIN TWO OF THE SEASON
SEEKONK, Mass. — For the second time in 2022, Jacob "Rowdy" Burns found his way to the front to carry the checkered flag in the Late Models on Saturday night. Burns used the outside lane to work from the bottom of the top-five to the front, rocketing past Josh Hedges for the top spot just before halfway, then driving away from the pack in the final laps to score the feature win.
Hedges led the opening laps — one week of his wedding — but Burns was able to slide around, leaving the race for second between DeGasparre and Hedges. Gerry was able to get around and finish in the runner-up spot, while Hedges finished in third. Richie Murray continued a consistent season with a top-five finish in fourth, while Vinnie Arrenegado finished out the top-five. Chase Belcher was sixth, followed by Mark Jenison, Ryan Floor, Jerammee Lillie and Luke Lebrun.
Out of the Sunoco Drive For The Cup drivers in round one, Lillie and Paul Lallier were eliminated from playoff contention.
The Late Models will return to the track for round two of the Drive For The Cup presented by Sunoco Race Fuel on Saturday, September 16. For more information on Seekonk Speedway, visit SeekonkSpeedway.com and follow the track on social media for the latest updates.


Ambulance staff and volunteers have been thanked for their hard work following a rise in calls over the three day weekend.
The East of England Ambulance Service NHS Trust (EEAST) received 1,185 emergency calls, in Cambridgeshire, during the three day May Day bank holiday – five per cent more than last year.
Sandy Brown, EEAST deputy chief executive, said: "We continue to experience high levels of demand and the bank holiday weekend was another busy one for the Trust. However, we were prepared and coped well, despite the demands being placed on the service.
Suffolk and Bedfordshire experienced the highest percentage increase in demand at 17% and 16% respectively.
Saturday was the busiest day of the weekend with more than 3,100 calls throughout its operating area.
This comes after a 17% increase in demand during the Easter bank holiday weekend.


Description: 2.4 acre building lots in very desirable north side semi rural location. Site has been, prepared with lots of fill, ready to build, area cleared for building your dream house, driveway, drilled well and septic approval. Ready to go Lot (Drainage plan available on request) Quiet location on paved Paquette rd with lots of new builds in the area and only minutes from town.


It can be tough to find the hot markets at first glance. Sometimes it takes a little digging and connecting with the right people to help you along your way. South Carolina Homes would love to share with you our research on the Charleston area and many other parts of South Carolina!


LEGO® MOVIE 2 review: 70840 Welcome to Apocalypseburg!
Coming 1 February 2019 (and already available for VIP members), LEGO® 70840 Welcome to Apocalypseburg!
is the largest and arguably most thrilling set from THE LEGO MOVIE 2: The Second Part. But how do the parts stack up? Sven Franic takes a look inside this 3178-piece set and its plethora of Sand Green.
The flagship set for THE LEGO MOVIE 2: The Second Part focuses attention on the part of the film featuring the derelict remains of Bricksburg from the first film (which may have some resemblance to New York?). This is an opportunity to jump on the revived pop-culture trend of the post-apocalypse dystopia and a great way for adult fans to connect with what is probably the closest The LEGO Group will touch a certain Ozploitation trilogy from our childhoods.
LEGO® MOVIE 2 review: 70830 Sweet Mayhem's Systar Starship!
Our series of set reviews of THE LEGO MOVIE 2: The Second Part continues today with 70830 Sweet Mayhem's Systar Starship! Ben Davies (ProfessorBrickkeeper) returns to examine another bumper collection of exciting parts.
One of the first sets revealed for the toy line and featuring prominently in the initial trailer for the film, 70830 Sweet Mayhem's Systar Starship! has been one of the most anticipated sets for The LEGO Movie 2, thanks in no small part to its unusual design, wide assortment of teal bricks, and inclusion of several new-for-2019 elements.
Before examining all the new parts, let's take a look at the construction of the ship and the finished model.
We've been eyeing off the new 2019 color and those new LEGO® gears for a few weeks now, and here both of them are in 70828 Pop-Up Party Bus! Ryan Howerter takes a look at this 1024-piece set which is priced £79.99 / US$79.99 / 89.99€, available at the usual suppliers including Amazon USA and Amazon UK.
Out of the 25+ sets revealed so far for The LEGO MOVIE 2: The Second Part, the Party Bus is the only one to include this year's new color: Vibrant Coral [TLG]/Coral [BL]. And boy, does it have a lot of it! Let's get started.
70824 Introducing Queen Watevra Wa'Nabi is the third set from THE LEGO® MOVIE 2: The Second Part that we are taking a closer look at – along with some commentary from Nick Vas, a LEGO Designer who was involved in its creation. It has 115 parts, including a new Lucy minifigure, Sweet Mayhem minidoll, Susan minidoll, and is now available priced £17.99/ 19,99€/ US$19.99 at Amazon USA and Amazon UK as well as all usual retailers.
First let's take a look at the new elements and printed parts in this small, colourful set.
LEGO® MOVIE 2 review: 70821 Emmet and Benny's 'Build and Fix' Workshop!
THE LEGO® MOVIE 2: The Second Part is assembling in cinemas in February 2019, and the tie-in sets have just been released in stores. 70821 Emmet and Benny's 'Build and Fix' Workshop! is the second set we are taking a closer look at. It has 117 parts, including new Emmet and Benny minifigures, and is now available priced £17.99/ 19,99€/ US$19.99 at Amazon USA and Amazon UK as well as all usual retailers.
70821 Emmet and Benny's 'Build and Fix' Workshop! is particularly aimed at preschoolers and young builders. Such sets were previously branded as LEGO® Juniors, now it seems they just carry a large 4+ age mark. The Juniors moniker was introduced for kids who knew they were getting too old for DUPLO and wanted "grown up LEGO"; perhaps the name was dropped as they didn't want something marked as junior either?
Conversely, it seems no grown up is too old for this set.
LEGO® MOVIE 2 review: 70827 Ultrakatty & Warrior Lucy!
THE LEGO® MOVIE 2: The Second Part is assembling in cinemas in February 2019, and we happened to stumble upon a few of the tie-in sets placed on the shelf early in a John Lewis store. We took this opportunity to review some of the sets before their official release starting with 70827 Ultrakatty & Warrior Lucy! This set contains 348 parts and is due for release 26th December 2018 in the UK priced at £24.99/ US$29.99/ €29.99.
Clearly, we have not yet seen THE LEGO® MOVIE 2: The Second Part but from the trailers and the various promotional information we know that it takes place five years after the end of the first movie. We saw some DUPLO characters appear just as the final credits started to roll and it seems those invaders turned awesome Bricksburg into a post-apocalyptic wasteland, now known as Apocalypseburg.
For the second year running, a new LEGO® hue is being introduced: 2019 sets will include Vibrant Coral, which has the colour ID 353. We simply cannot wait to get our hands on it, so instead we asked LEGO colour aficionado Ryan Howerter to guess how it might look!
Nothing gets me as excited about new LEGO sets as much as brand-new colors, and given The LEGO Group's modern palette constraints – a color has to be removed from the palette to make room for any additions – that doesn't happen very often. So it was a pleasant surprise to see salmony parts in the new The LEGO Movie 2 set 70828 Pop-Up Party Bus.
LEGO has been very good at introducing new colors in a wide variety of basic and specialized parts within the first year after launch, so instead of focusing on the few shapes it comes in so far, let's explore the potential of the color itself!
We sent a varied selection of new LEGO® parts to some fan builders to explore techniques and models. This time we have the talented Steve Guinness: one half of the team who won Series 1 of Channel 4's LEGO Masters who now undertake commissions as The Brick Guys.
When I saw the 1x3 jumper plate (Design ID 34103) I liked the unusual pattern on the underside, as it has no anti-studs or pegs. The tiny triangles reminded me of teeth so I came up with these Clockwork Robots.
On the last weekend of each September, the Skærbæk Fan Weekend brings together hundreds of LEGO® fans from dozens of countries for a few fun-filled days in a remote Danish coastal town. 2017's was the biggest yet, and on the Sunday morning New Elementary ran one of our 'live' parts festivals: a special workshop where, thanks to the LEGO Group, 60 AFOLs got their hands on some of the newest LEGO pieces to see what they could build within the space of an hour.
At long last I'm ready to show you what they made! Well, almost. Today I will introduce the parts I chose for the festival.
Somewhere in among designing his latest range of gorgeous Christmas ornaments, Chris McVeigh managed to find the time to crack open THE LEGO® BATMAN MOVIE 70922 The Joker Manor for us and, having assembled its 3444 pieces, dissected it again to locate all the exciting new and recoloured LEGO elements - including its completely new rollercoaster system! The set is now available priced £249.99 / US$269.99 / 269.99€.
The Joker Manor is a sprawling set that imagines Wayne Manor has been overtaken and aggressively remodelled by the Joker (as seen in THE LEGO® BATMAN MOVIE). It's a brilliant display piece with a glitzy, colourful entrance, oversized spring-loaded boxing gloves, a garish, glaring tower, and naturally, giant "The Joker" branding. However, the real showstopper is the rollercoaster that encircles the manor. With this set LEGO introduces an all-new car and track system that is sure to appear in many upcoming product lines, from City to Creator Expert.
In this article I'll closely examine the new rollercoaster elements, highlight other new parts, and discuss interesting recolours and reissues.
Today, Chris McVeigh (powerpig) reviews the fantastic new range of LEGO® parts found in 70620 NINJAGO City, the largest of the sets from The LEGO NINJAGO Movie range, which went on sale this month priced at £259.99 / US$299.99 / 299.99€.
At 4867 parts, NINJAGO City is one of the biggest LEGO® sets ever. It's visually rich, incredibly detailed, and great fun to build.
The city itself is divided into three sections, coinciding with three hefty building guides. Level 1: The Old World is built atop a murky waterway. On that level you'll find a fish market, robot maintenance room, and the base of the elevator. Level 2: The Street is a busy pedestrian area that is home to shops and services, including a comic book store, clothing store, and crab kitchen. Up on Level 3: The High Rise, you'll find Lloyd's and Misako's shared apartment, a rooftop sushi restaurant, and a luxury bathroom.
In this article I'll discuss new parts and how they're used, highlight some of the more interesting recolours, and then look at the set's clever roofing techniques.
We left you on a bit of a cliffhanger when we showed you Kevin Levell's initial creations for our parts festival using the LEGO® NEXO KNIGHTS™Combo Power shield. Wait no more: let's blast off into Classic Space!
I'll admit, I got a bit carried away after I had the 'Hab/Dome' built.
We have an unusual set to discuss today in that it contains a high percentage of newly recoloured elements in a single colour. To discuss the Medium Nougat [TLG]/ Medium Dark Flesh [BL] pieces in LEGO® Batman Movie set 70904 Clayface Splat Attack we welcome a new author: Sven Franic (Flickr: svenfranic) who is a member of a LEGO User Group from Croatia, Kockice.
One of the main frustrations or challenges when building your own LEGO creations, depending on your point of view, is the limited number of colours a certain element is available in. This is especially true for those who like to build concepts in digital form, only to realize some crucial elements are not available in that shade. Some colours are so limited in choice of parts that nobody really sets out to build with them and it is just more convenient to stick with the commonly available colours. I am personally a bit tired of grey and brown. It is time for a colour revolution!
Is 2014 just the best year of LEGO® sets ever?? Of course not... that was 1979. But this summer's wave of new sets contains some absolutely thrilling sets. If it weren't for the upcoming LEGO Ideas Exo-Suit, I'd say that my most anticipated set of 2014 was 70816 Benny's Spaceship, Spaceship, SPACESHIP!
Of course, I'm biased because this set represents the ultimate in nostalgia for me, but that also brought a huge weight of expectation to this build. Could a modern set really evoke the kind of love I felt for my Space sets as a kid? I was really worried it wouldn't capture the intangible magic of Classic Space and just leave me feeling like it was any other modern-day Space set but in blue/grey/trans-yellow. I'm happy to report that this was not the case at all.
Somewhat delayed by life in general, here at last is my final review completing the first wave of The LEGO® Movie sets; 70813 Rescue Reinforcements. You get a lot in this set (it has the greatest piece count of this first wave) and the completed build consists of a Micro Manager, a chunky mech made from a fire truck and a kooky helicopter made from a windmill. You don't get to see the 'original' forms of these as the set doesn't have the alternate instructions to build them. Nor did I spot them in the film itself - only the transformed versions - but perhaps like so much else in the film it was a case of blink and you'll miss it.
I discussed 70803 Cloud Cuckoo Palace back when pictures were first released, and given it's a fairly simple and flat build, I haven't too much more to say now that I have the actual set in hand. But things did take an unexpected creative turn when I mailed one of its elements, which comes in Lime [BL]/Bright Yellowish-Green [TLG] for the first time, over to spacey chap Peter Reid. He's perhaps most famous for designing the Exo Suit which will be developed by TLG to become the next CUUSOO set, but another trademark build of Pete's is his MkIII M364 Turtle. Let's hand over to Pete to explain what this new element meant to him.
well here's some further inspiration for you!
ReBrick, the MOC bookmarking site run by TLG, are running a competition with some rather unique LEGO Movie prizes. To enter you must build an alternate model using only the pieces from one official set of your choice. It's for 16 year-olds and over and closes at the end of March.
Hey, this seems like a good chance to remind ourselves of the alternate models we've come up with here at New Elementary over the last month!
Following James Pegrum's look at 70806 Castle Cavalry, today I'm reviewing all three of the other "2-in-1" sets from The LEGO® Movie series; 70805 Trash Chomper, 70811 The Flying Flusher and 70804 Ice Cream Machine.
On reviewing and rebuilding duty today we have James Pegrum, a prolific builder famed for his British history series (his model of WWII code-breaking computer Colossus sits on display in Bletchley Park next to the real thing!) and his realistic Castle builds. At 2013's STEAM exhibit in Swindon, UK, he built the massive castle and grounds for The Land of Tigelfah group display and recently he's entered seven categories in CCC XI (the eleventh annual Colossal Castle Contest). Given these honourable credentials I thought it would be interesting, or perhaps horribly cruel, to send him 70806 Castle Cavalry.


text:
'use strict'

const argx = require('argx')
const apemanfile = require('apemanfile')
const co = require('co')
const arrayreduce = require('arrayreduce')
const arrayfilter = require('arrayfilter')
const ShowLogger = require('./logging/show_logger')
const dig = require('./digging/dig')

/** @lends apemanShow */
function apemanShow (keypath, options) {
  let args = argx(arguments)
  options = args.pop('object') || {}
  keypath = args.remain().reduce(arrayreduce.arrayConcat(), []).filter(arrayfilter.emptyReject())
  if (Array.isArray(options)) {
    keypath = keypath.concat(options)
    options = {}
  }
  let keysonly = !!options.keysonly
  return co(function * () {
    let configuration = apemanfile(options.configuration)
    let data = dig(configuration, keypath)
    if (!data) {
      throw new Error('Not found: ' + keypath)
    }
    let logger = new ShowLogger({})
    if (configuration.$src) {
      logger.notice('[show] %s', configuration.$src)
    }
    if (keysonly) {
      data = Object.keys(data)
      logger.debug('keysonly: true')
    }
    logger.logShowed(data)
    return data
  })
}

module.exports = apemanShow

redpajama_set_name: RedPajamaGithub


text:
Businesses weigh power co-op plan
NORMAL, ILLINOIS - The days of simply writing a check to the utility company are over.
"No more folks," said Bonnie Grady, senior associate with CQI Associates, an energy management consulting team based in Maryland. "This is an important topic that is not going away. You have to pay attention to how you're paying for electricity if you w nt to keep your business flourishing."
In other words, business owners should shop around for a good price because deregulation law allows multiple suppliers to provide power, Grady told a group at Heartland Community College in Normal. That competitive bidding could offer 6 percent to 15 percent savings the first year, depending on an organization's size.
As utility rates continue to rise, those figures could double in the second year and again in the third, Grady said. Pamela Sweetwood, a board member of the Humane Society in Normal, likes the idea. "Anything we save is more pets we can help," she said. "That's the bottom line."
The group of about 50 McLean County businesses, not-for-profit organizations and government entities was doing some homework about a recently proposed McLean County Chamber of Commerce electrical cooperative. Co-op participants can buy power from another supplier, but AmerenIP still would provide delivery services.
Corn Belt Energy Corp. members are unable to participate in the program because of Illinois regulations. CQI Associates has worked to form cooperatives with chambers in Decatur, Peoria and Champaign this spring. The company now expects to bid for a two- or three-year power contract for McLean County along with chambers in Springfield, Logan and Effingham o the same day this fall, thus increasing the chance for a better deal.
"It just makes sense," Grady said. "It's power in numbers." The program makes sense for Mike Flanigan, manager at The Alamo II in Normal. Grady looked at Flanigan's electric bill and told him what he already figured - his bill is high enough that a co-op could save him money.
"If I can save 6 percent... the benefit's just too great not to (sign up)," Flanigan said. Businesses that pay more than $200 a month for their electric supply will benefit the most, Grady said. But there is no guarantee members' cost will always be cheaper with their supplier. The main goal is for participants to find long-term budget stability, Grady said. The deadline to enroll in the co-op is Aug. 3. The membership fee is $300 per location. Fees will not exceed $3,600, regardless of the number of locations.
Knight Ridder Tribune
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One of our first Barbour Jacket Customers from last year spotted on the East Village's wonderful 9th Street. And her Bedale jacket looks good as new.
He looks great in this quilted Barbour Vest but he's kindly giving it to his boyfriend as a Christmas gift.


SSH Factory is a set of Java based client components for communicating with SSH and telnet servers.
Jagacy 3270 is a feature rich 3270 terminal emulator and screen-scraping library written entirely in Java. It supports SSL, TN3270E, and over thirty languages. The emulator can be configured to help create screen-scraping applications.
Jagacy VT is a feature rich VT100/VT220 terminal emulator and screen-scraping librarywritten entirely in Java. It supports SSL, ANSI and XTERM protocols. Theemulator can be configured to help create screen-scraping applications.


text:
<!DOCTYPE html>

    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="src/main.css">
    <link rel="stylesheet" href="node_modules/antd/dist/antd.min.css">


Back together, this should be interesting.
Uh oh. Sometimes being too talented can lead to trouble.
Should'na'ough'ta done that. At least he didn't puncture or short the battery and set it on fire.
"In the ocean"… could be worse, could be in a Spinosaurus.
But if the "I wanna hang with the mellinials" queen archetype starts sending selfies in order to brag. She could inadvertently tip her location from the background. Lots of couples become singles that way.
Lordie, with her retinue, just imagine the photo-bomb opportunities.