Synthesis of a novel A-b-(B-co-C)-type terpolymer with a regioregular poly(3-hexylthiophene) segment and its application to intrinsically stretchable transistor memory

Abstract

To date, a variety of organic semiconductors with high stretchability have been developed for applications in wearable electronic devices. However, there is still a problem of irreversible damage by repeated stretching/releasing cycles, resulting in a low lifetime for the devices. In this study, a novel A-b-(B-co-C)-type terpolymer, where A and B-co-C were regioregular poly(3-hexylthiophene) (P3HT) and poly(nbutyl acrylate-co-acrylic acid) segments, respectively, was successfully synthesized by the copper-catalyzed azide-alkyne cycloaddition reaction of α-chain-end-functionalized P3HT with an azide moiety and α-chain-end-functionalized poly(nbutyl acrylate-co-tbutyl acrylate) with an alkyne moiety, followed by deprotection of tbutyl groups with trifluoroacetic acid. The AFM and OM images of the terpolymer films showed that no cracks formed even when stretched up to 100%. This may be due to the synergistic effect of the low Tg-inducible nbutyl acrylate and hydrogen-bonding-inducible acrylic acid repeating units in the copolymer segment. In addition, the results of organic transistor memory using terpolymer thin films showed that the transferred/stretched electrets could preserve their device performance and produce stable bipolar charge trapping by applying electrical writing/erasing processes.