PRESENT INDUSTRY STATUS SRI LANKA

The properties of ceramics that make them suitable for seals are their hardness, low friction, high resistance to corrosion and high temperature capability. Therefore the overall performance of the ceramic seals is much better than that of the seals made from conventional materials such as rubber, nylon and teflon. Face seals are used in many applications including sand slurry pumps, chemical processing and handling, fuel pumps (eg. off shore recovery of crude oil), washing machines, dishwashers and garbage disposal. Graphite, SiC, A12O3, ZrO2 and Si3N4 (including sialons) have been used successfully for all types of seals.

Applications in medicine (for new orthopaedic devices, auditory prostheses, heart valves, dental implants and tissue substitutes) is another important area that cannot be left out in this discussion. Significant advances have been made in this regard during the past few years because of the encouraging results that have been observed.

Excellent bio-compatible properties such as the surface activity of bone adhesion, porous structures, wear and abrasion resistance, greater chemical inertness of bio-ceramics have contributed to these advances. Porosity plays an important role in the successful use of bio-ceramics, since a natural form of fixation results if tissue grows into it. Al2O3, hydroxyapatite, calcium phosphates, carbon composites, surface and glass ceramics (CaO-SiO2 based hydroxyapatite) are the leading bio-ceramic materials. Most of the raw materials required are found in mineral form in Sri Lanka.

Since the discovery or semiconductor materials, development of devices based on p/n junctions has resulted in unprecedented technological innovations, and the understanding of the functioning of these devices has become a challenge to the scientists. Diodes of various types (signal diodes, rectifier diodes, veractor diodes, Zener diodes, photo-diodes etc.,), transistors (bipolar and FET), semiconductor / silicon controlled rectifiers (SCR), diacs, and triacs are all devices based on one or more p/n junctions. Light Emitting Diode, LED is basically a p/n junction device that emits light when a current is passed through it. It converts electricity into light. Nanotechnology plays a key role in producing these devices.

NANOTECHNOLOGY BUSINESS STARTUP

Basic requirements

There are several fundamental needs to consider when transitioning nanotechnology discovery into a business, and ultimately the marketplace. These needs include steady cash flow, market focus, the right pool of skills, correct timing, and adequate funding. Developers of a nanotechnology business must establish a steady flow of fiscal resources.A mix of government and private funding can support the research phase, where the level of funding can remain slow and steady. However, a more public approach is required to accelerate the business growth phase.

A nanotechnology business must also develop a marketing plan. The business must critically evaluate and qualify potential markets, identify lead customers within each market, and develop a business strategy for successful market penetration. For instance, Nanophase offers engineered solutions to meet customers' specific requirements. The correct skills set establishes the right chemistry for success.

Once potential markets are identified, all functional areas must merge – including research and development, process engineering, and business development functions - to collectively determine how core technologies can serve multiple commercial markets, how to improve and evolve the company's manufacturing technologies, and how to develop new nanomaterials and applications that provide value to current and potential customers.

The duration of the research phase is unpredictable, whereas the growth of a business is much more controllable once opportunities are identified. The key is to balance execution between sales, scaling processes to meet customer needs, and developing new solutions. Integral considerations for turning an idea into a commercial product or service also include a keen sense of the marketplace, knowledge of intellectual property, and regulatory considerations for various industries.

Potential to have industry startup in Sri Lanka

New industries based on Clay Nano-Particles

Such a cheap source as clay may be used in many advanced technologies, and industries based on clay nanoparticles and clay-polymer nanocomposites are to be exploited.

When saturated with water, clays develop interesting properties such as thixotropy, and these are exploited in various spray applications. The liquid like flow exhibited by waterlogged clays is the cause of landslides that are common in Sri Lanka. On the other hand these properties are exploited in the multi-million dollar drilling mud industry. The cation exchange properties of the clays can be exploited for water softening, water treatment, pollutant removal etc.

Certain cation exchanged clays act as initiators for the polymerization of organic compounds, and some of the resulting clay polymer composites show extremely interesting mechanical and electrical properties. When the clay structure is broken down by the action of strong acids, the broken bonds are associated with protons and the resulting amorphous materials are strong solid acids. These were the first catalysts used for petroleum cracking. Although their role as cracking catalysts has been replaced by the synthetic zeolites, there is a resurgence of interest in their use as catalysts for specific organic conversions. The so-called no carbon copy paper is designed using acid treated clay/pigment combinations. Acid treated clays such as Fullers earth is used for the decolourisation of vegetable oils.

When the interlayer cations are replaced by protons, the clays become strong acids and are comparable in strength to concentratd HCl. They are currently being extensively studied as acid catalysts for chemical and pharmaceutical industry. Being solid acids they can be easily separated after reaction and re-used, and their use does not result in environmental pollution, which is the problem with mineral acids. With the current accent placed on "Green chemistry", acid clays have the potential to be excellent acid catalysts, and countries such as India have advanced research programmes for such uses. Although the acid clays are good catalysts, they suffer from the disadvantage of being unstable above 500 &degreeC.

The so-called pillared clays prepared by replacing the interlayer cations with large polymeric inorganic ions such as the Al-13 Keggin ion, where the sheets are permanently propped apart by inorganic oxide columns, combine high surface area (>700m2g-1) with catalytic activity and thermal stability up to about 700&degreeC. They are both Bronstead and Lewis acids and a wide variety of reactions such as dehydrations, alkylations, esterifications, oxidations and Diels Alder reactions can be catalysed by them. In addition, the fact that the reactions occur within the clay has the potential of steric and even optical control.The pillared clays are also good adsorbents and thus offer potential for gas separation, purification and as catalyst supports. Research has led to the synthesis of electronically conducting polymer-modified clays. These clays are superior compared to alkylammonium clays in removing environmental pollutants. The electronic conductivity of these materials has also been studies and found that these nanocomposites have applications in polymer batteries.

New industries based on High-Tech Ceramics

Manufacturing high-tech ceramics is another advanced industry worth multimillions in foreign currencies.This is a matter of converting our mineral sands into useful products through nanotechnology. The materials will have limitless applications in spare parts for high-temperature devices, engine components, sealers, and so on.

Almost all the ceramic materials have high compressive strength and resistance to abrasion. Therefore they are excellent as abrasive powders and for incorporating in grinding wheels. MgO, A12O3 and diamond powders are used for metallurgical polishing. Silica particles are used in sandstones and sandpaper. SiC and diamond are superior for these purposes. Locally available hard minerals such as corundum, zircon, silica, etc. have been used successfully in manufacturing grinding wheels, in Professor B.S.B. Karunasratne's laboratory in the Department of Physics, University of Peradeniya.

The extreme hardness, wear resistance and low contact friction of ceramics, have also been utilised in the manufacture of bearings. For example, Si3N4 sliding on Si3N4 has a coefficient of friction about 0.27 without addition of a lubricant, whereas steel sliding on steel has a coefficient of friction about 0.12 with oil lubrication and 0.54 without lubrication. However, the lubrication properties of ceramics depend on the chemical composition, temperature and operating condition of the environment. In particular, these ceramic bearings are useful where lubrication is either limited or not possible (vacuum environment) or the temperature is beyond the limits of metal bearings. An example in a low-load situation is the use of ruby or sapphire (single crystal A12O3) bearings in watches. Ceramics have an advantage over steel, because of lower density which reduces the centrifugal force on the balls. This in turn reduces the excessive wear of the bearings.

Apart from this, the contact area between ceramic balls and the ring is smaller due to the high elastic modulus of ceramics, and therefore a lower amount of heat is generated. Hot-pressed Si3N4 has shown success in high-load, high speed bearing applications.

New industries based on Graphite

Excellent lubricants may be prepared by dispersing graphite nanoparticles in a viscous organic liquid. This would benefit the graphite industry enormously. Even gaskets could be manufactured. Graphite nanoparticles with a suitable binder may be pressed to form electrodes. The alkaline-manganese dioxide (Zinc/KOH/MnO2) primary battery has become the dominant battery system in the portable battery market after introducing these type of batteries in 1960. Zn is the most popular anode material and Manganese dioxide is an abundant natural oxide, inexpensive and non-polluting material used as cathode in alkaline primary batteries. MnO2 is also an electronic conductor. Although it is a poor electrical conductor, the electronic conductivity can be improved by addition of carbon black or graphite. Graphite is a good additive to MnO2 but a trace amount of impurities in natural graphite affects adversely to electrical conductivity.

Therefore the morphology and occurrence of Sri Lanka natural graphite has to be selected very carefully in such applications. Then again the most suitable form will be the nanoparticles.

New industries based on solid polymer batteries

The lead-acid battery developed in 1859 is still used for ignition in motor vehicles and for propulsion in electrically powered vehicles. Most common types of batteries used for portable electronic devices are Carbon-Zinc, Alkanline, Ni-Cd,, Ni-MH etc. However, these batteries do not meet the power requirements demanded by the electric vehicle industry and the consumer electronic industry due to limited specific capacity (ampere hour per gram of active material) giving rise to low energy densities (watt hour per kg). Although microelectronic industry has gone through an unprecedented development during the last few decades, the portable electrochemical power sources have shown only a very slow progress.

Lead-acid and Ni-Cd batteries have 30-100 Wh/Kg (and 50-150 Wh/litre). High energy density and power density, long cycle life and shelf life, reliability and safety are some of the key features expected from a battery. Lithium based rechargeable polymer batteries are emerging as the electrochemical power source of the future. There are several different types of rechargeable Li-polymer batteries that are being commercially developed:

Systems with Li anodes: Li/SPE/TiS2 (Intercalation cathode)

Other cathode materials: V2O5, V6O13, LiV3O8, LiMn2O4, ;

Recent developments: LiNiO2, LiCoO2 These cathodes can have potentials 4V against Li metal.

Typically, a Li/SPE/LiCoO2 battery can have energy densities of 440 Wh/kg

New Industries based on active carbon:

Electrochemical supercapacitors

Electrochemical capacitors are devices capable of higher storage, several hundred times more than conventional capacitors. There are no chemical changes and unlimited cyclability compared to batteries. The critical components of supercapacitors include the electrodes, electrolyte and the separator. The characteristics of electrode materials for supercapacitors include high cyclability, long-term stability, high surface areas and resistance to electrochemical oxidation/reduction.

Carbonaceous materials have been particularly popular owing to their large surface areas. High temperature heat-treated active carbons such as coconut shells, wood powders, coal tar and resins are active electrode materials with surfaces ranging between 1000 and 500 m2/g, that results in capacities as high as 500F/g in alkaline electrolytes.

Discussed above are only a few possibilities but of course, the potential for new industries based on locally available raw materials is limitless. The variety of properties and uses for these myriad materials fashioned into remarkable products is truly remarkable in itself. That such apparently mundane and plentiful minerals could be fashioned into materials with properties so diverse, is a testament both to the wonders of nature and to the agility of the human mind.
CONCLUDING REMARKS

"This is not to say that nanotechnology is a far-off, fuzzy, futuristic technology. It is not. It has already established a beachhead in the economy. The clothing industry is starting to feel the effects of nanotech. Eddie Bauer, for example, is currently using embedded nanoparticles to create stain-repellent khakis. This seemingly simple innovation will impact not only khaki-wearers, but dry cleaners, who will find their business declining; detergent makers, who will find less of their product moving off the shelf; and stain-removal makers, who will experience a sharp decrease in customers. This modest, fairly low-tech application of nanotechnology is just the small tip of a vast iceberg – an iceberg that threatens to sink even the "unsinkable" companies."

In this respect, nanotechnology is not different from other new disciplines. We, as humans, do not seem to have the capacity to really learn to understand something before we start to mess with it on a big scale.

And when things do go wrong – just imagine an autodidactic nano-intelligence on the loose – we end up fighting the symptoms, pointing fingers at each other, and deny any or all culpability.

Forethought of possible consequences is usually far from our minds as we are caught up, or pushed by superiors, to make the research investment profitable as soon as possible. Money seems to be all that matters these days, and so it is with nanotechnology. It will need to prove itself in the boardroom as much as the laboratory otherwise it will go the way of other developments that failed the "money test" and disappear into the archives and filing cabinets of the world.

Our sincere thanks should go to Prof. Ray Fernando, California Polytechnic State University, USA, Prof. RMG Rajapakshe, University of Peradeniya, Sri Lanka for their valuable inputs & kind guidance.

"STRIDE INTO THE FUTURE BEFORE IT ARRIVES"

TECHNOLOGY WATCH CENTER (TWC)

Technology Division

National Science Foundation, No. 47/5, Maitland Place,

Colombo – 07, SRI LANKA.

Tel/Fax – 2676766

Email: twclanka@nsf.ac.lk

www.twc.nsf.ac.lk

This booklet was compiled by Ms. Pradeesha Warnasooriya on behalf of the Technology Division of NSF.
