Synthesis and characterization of A2B Miktoarm Star Copolymers Composed of Regioregular Poly(3-hexylthiophene) and Poly(methyl methacrylate) containing rigid core

The $\pi$-$\pi$ interaction between P3HT arms in Miktoarm star copolymer composed of P3HT and PMMA ((P3HT)2PMMA) was strong enough to arrange two P3HT backbone chains in (P3HT)$_2$PMMA to stack one by one along the nanofibril axis on thin film. This is because of very small $\pi$-$\pi$ stacking distance between P3HT backbones compared with the size of the core. Here, we report a facile synthesis of (P3HT)$_2$PMMA containing rigid core. First, we synthesized coupled P3HT having 1,3-diazidobenzylaldehyde at the center using click reaction between mono-ethynyl P3HT and 1,3-diazidobenzylaldehyde. The aldehyde at center in coupled P3HT was replaced by ethynyl group using Grignard reaction with ethynyl magnesiumbromide (P3HT-core-P3HT). Then, copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition click reaction between P3HT-core-P3HT and PMMA-N$_3$ was performed to synthesize (P3HT)$_2$PMMA. The optical property and self-assembly of (P3HT)$_2$PMMA was investigated.