(164d) Conjugated Grafted Polymers for Electrochemical Transistors

Electrochemical transistors are promising devices that may lead to new applications in bioelectronics. The mechanical mismatch between bioelectronic devices and biological tissue can lead to problems with long-term stability, thereby motivating the need for soft conducting materials. To this end, this work describes the synthesis of conjugated grafted polymers as organic electroactive materials. The targeted brush architectures are hypothesized to provide soft mechanical properties due to reduced polymer entanglements. We used four schemes for the synthesis of graft polymers ranging from fully conjugated to semi-conjugated (with either the side chains or the backbone conjugated) to completely unconjugated for comparison. Using coupling techniques (Suzuki Coupling and Kumada Coupling) and controlled radical polymerizations (reversible addition-fragmentation chain-transfer and atom transfer radical polymerization), we have synthesized polystyrene and poly(carbazole-co-diketopyrrolopyrrole) polymer backbones functionalized with azide groups on each repeat unit. Using these techniques, we also synthesized poly(methyl methacrylate) and poly(3-hexylthiophene) end capped with alkyne groups as our side chains. We utilized a grafting-to approach with a copper-catalyzed azide-alkyne cycloaddition to tether the side chains to the backbones.