Click synthesis of an adhesive block copolymer with poly(3-hexylthiophene) and poly(vinyl catechol) segments

Abstract

Semiconducting polymers have garnered considerable attention from researchers, as these polymers are potentially applicable to flexible/stretchable organic electronics. However, although the adhesiveness of these materials on substrates is an important characteristic, it has rarely been investigated. Herein, we synthesized and characterized a novel block copolymer, poly(3-hexylthiophene)-b-poly(vinyl catechol) (P3HT-b-PVC), with improved adhesion properties. P3HT-b-PVC was successfully synthesized via a copper-catalyzed azide–alkyne cycloaddition reaction between chain-end-functionalized P3HT with an alkyne group (P3HT-Alkyne) and chain-end-functionalized poly(3,4-di-tert-butyldimethylsilyloxystyrene) with an azide group (PSVC-Azide), followed by deprotection of tert-butyldimethylsilyloxy groups from the PSVC-Azide segment. Tape test results showed that the adhesion property of the P3HT-b-PVC film was considerably better than that of the corresponding P3HT film. Furthermore, despite the presence of an insulating PVC block in P3HT-b-PVC, the P3HT-b-PVC thin film exhibited a hole mobility of 1.1 × 10−5 cm2V−1s−1, which was comparable to that of the corresponding P3HT thin film (1.8 × 10−5 cm2V−1s−1). To the best of our knowledge, this is the first study to elucidate the primitive adhesion properties and charge mobility of P3HT-based block copolymers. The proposed synthetic approach may be extended to develop various block copolymers with other π-conjugated polymer segments, providing new avenues for various applications that require highly-adhesive materials. A novel block copolymer, poly(3-hexylthiophene)-b-poly(vinyl catechol) (P3HT-b-PVC) was successfully synthesized via a Click reaction between chain-endfunctionalized P3HT with an alkyne group (P3HT-Alkyne) and chain-end-functionalized poly(3,4-di-tert-butyldimethylsilyloxystyrene) with an azide group (PSVC-Azide), followed by deprotection of tert-butyldimethylsilyloxy groups from the PSVC-Azide segment. Tape test results showed that the adhesion property of the P3HT-b-PVC film was considerably better than that of the corresponding P3HT film. Furthermore, despite the presence of an insulating PVC block in P3HT-b-PVC, the P3HT-b-PVC thin film exhibited a hole mobility comparable to that of the corresponding P3HT thin film.