All-Conjugated, All-Crystalline Donor–Acceptor Block Copolymers P3HT-b-PNDIT2 via Direct Arylation Polycondensation

Abstract

The synthesis and characterization of all-conjugated, all-crystalline donor–acceptor block copolymers (BCPs) containing poly(3-hexylthiophene) (P3HT) and poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (PNDIT2) is presented. Direct arylation polycondensation (DAP) of dibromonaphthalenediimide and bithiophene is carried out in the presence of P3HT end-cappers to allow the in situ formation of BCPs P3HT-b-PNDIT2. As-prepared, well-defined H-P3HT-Br with hydrogen and bromine chain termini shows nonoptimal reactivity under the DAP conditions used. Therefore, H-P3HT-Br is converted into either H-P3HT-Th (thiophene) or H-P3HT-Mes (mesitylene), giving α,ω-hetero-C–H functionalized P3HT with modulated C–H reactivity. The influence of the different C–H chain termini of P3HT on the ability to act as end-capper and the resulting block structures is investigated in detail using wavelength-dependent size exclusion chromatography (SEC) and NMR spectroscopy. Di...