Synthesis and self-assembly of a diphenylalanine–tetraphenylethylene hybrid monomer and RAFT polymers with aggregation-induced emission

Abstract

A hybrid monomer consisting of diphenylalanine with the self-assembling ability and tetraphenylethylene (TPE) with aggregation-induced emission (AIE) properties was synthesized and employed for reversible addition–fragmentation chain transfer polymerization. The diphenylalanine–TPE hybrid monomer (APhePheTPE) self-assembled into helical nanoribbons and fiber-like structures and exhibited AIE properties with blue emissions, which originated from the aggregation of TPE units by tuning the water fraction in the tetrahydrofuran/water mixtures. The APhePheTPE revealed the formation of β-sheet structures and aggregation-induced circular dichroism (AICD) by achiral TPE units via interactions with diphenylalanine moieties. The APhePheTPE homopolymers showed the feasibility of forming stable assembled structures, such as rod-shaped structures and nanofibers, with characteristic molecular weight-dependent emissions and AIE properties. This study revealed the potential of the polymerizable diphenylalanine–TPE hybrid monomer as a building block for the development of chiral AIE hybrid polymers with the ability to form various self-assembled structures and characteristic AIE and AICD properties.