Influence of the Presence and Length of an Alkyl Spacer on the Supramolecular Chirality of Block Copoly(thiophene)s

Three block copolymers, P3AT-1-b-P3AOT, P3AT-2-b-P3AOT, and P3AT-6-b-P3AOT, composed of an alkyl- and alkoxy-substituted poly(thiophene) block which are connected by a nonconjugated flexible alkyl spacer of variable length, were synthesized by coupling the azide- and acetylene-functionalized homopolymers using the click reaction. GPC and H-1 NMR analysis confirmed the formation of the block copolymers. Next, the influence of the presence and length of the alkyl spacer on the electronic properties was investigated with UV-vis and emission spectroscopy. Also, the influence of the length of the alkyl spacer on the aggregation behavior was studied with UV-vis and CD spectroscopy, which is possible due to the chirally substituted P3AOT block. All these experiments revealed that the supramolecular structure of the P3AT block is affected by the P3AOT block, but if a long alkyl spacer is present between the blocks, an additional reorganization of the P3AOT block is possible, which is not the case for shorter alkyl spacers or in the absence of a spacer.status: publishe