Polymer brushes are polymers in which individual polymer chains stand side by side on a surface, causing the chains to stick out like bristles on a brush. In the journal Angewandte Chemie, American scientists have now presented a new simple method for making three-dimensional nanostructures in a controlled fashion from polymer brushes.
There are a wide variety of current and future applications for polymer brushes. For example, a coating of polymer brushes on a plastic surface such as an artificial heart valve or a dialysis machine can hinder the adsorption of proteins onto the surface. It can also be used in the fabrication of next-generation microelectronic devices. Other areas of application include biocompatible coatings for implants, chemical sensors, and new “intelligent” materials.
Although progress has been made with regard to new brush structures, current methods do not offer sufficient temporal and spatial control over the growth process. Usually, a self-organized monolayer of an initiator is assembled on a substrate and the polymer chains can grow out from there. In order to obtain specific patterns, the initiator must be applied to the substrate in a corresponding pattern—a complex undertaking that is not manufacturable and does not allow for the generation of complex three-dimensional structures.
Craig J. Hawker and a team from the University of California, Santa Barbara, and TheDow Chemical Company (Midland, Michigan) have developed a new method that allows for the formation of brushes on a uniform initiator layer with both spatial and temporal control. Their simple method is based on a light-activated radical polymerization. The length of the bristles at any given location depends only on the duration and intensity of the local irradiation.
Read more at: Phys.org