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PHOTOCROSSLINKED IMMOBILIZATION OF POLYELECTROLYTES FOR TEMPLATE ASSISTED ENZYMATIC POLYMERIZATION OF CONJUGATED POLYMERS
Description:
Growing demand in consumer electronics raises need for efficient, affordable, environmentally benign and biodegradable substitutes for current technologies. Printed circuit boards contain heavy metals such as antimony, silver, chromium, zinc, lead, tin and copper. According to some estimates there is hardly any other product for which the sum of the environmental impacts of raw material, extraction, industrial, refining and production, use and disposal is as extensive as for printed circuit boards. Consumer electronics constitute 40% of lead found in landfills. Lead can cause damage to the central and peripheral nervous systems, blood system and kidneys in humans. In recent years there has been a tremendous interest in the use of conductive polymers in electronics applications because of their wide range of electrical, electrochemical and optical properties as well as their good stability. This proposal addresses the need for environmentally friendly printed circuit boards manufacturing technology. The following method is proposed to pattern a substrate with a biodegradable, non-toxic material which serves as template for enzymatic synthesis of conductive polymer. Horseradish peroxidase has been demonstrated to catalyze the oxidative polymerization of aniline to form conductive polyaniline.
This process is facilitated by the presence of a macromolecular template with sulfonic acid groups that provide a unique environment for the formation of the conducting polymer. Photocrosslinking thymine containing photopolymers with pendant phenylsulfonate groups is expected to yield a viable templating substrate. This will allow for the water soluble environmentally benign photopatterning of a conductive material. Thymine-based photo-polymers have many environmental and performance advantages. First, they can be water-soluble. This avoids the need for organic solvents, an environmentally beneficial objective on its own. Secondly, the process is not a polymerization reaction. These water soluble, nontoxic polymers are already polymerized. This photoreaction initiates a crosslinking mechanism where neighboring strands are "tied" together. The formation of networks in this way, leads to insolubilization. Finally, the non-irradiated material can be collected and reused. This grant will give graduate students at UMass Boston the opportunity to carry on innovative work on the development of conductive polymer films. In addition, this project helps build the laboratory curricula for photoreactivity of DNA, template guided synthesis, layering as an architectural principle, and enzymatic processing and catalyzed reactions. At the graduate level, this project provides opportunities for understanding the fundamental chemistry and physics of pi-bonded macromolecules, the metalinsultator transition, doping processes.