Hierarchically self-assembled helical aromatic conjugated polymers

We review recent progress in hierarchically self-assembled helical aromatic pi-conjugated polymers (ACPs) by focusing on (i) the intrachain helicity of ACPs in which the main chain forms a helicene-like helical conformation and (ii) the interchain helicity of ACPs in which the main chains are helically pi-stacked with one another. In Part 1, intrachain helical poly(meta-phenylene ethynylene) derivatives are discussed in terms of thermodynamic stability, usage of a chiral template, and feasibility of chiral recognition. Intrachain helical poly(meta-phenylene) derivatives are discussed from viewpoints of hierarchically self-assembled whiskers, magnetically forced macroscopic alignment, and chemical modification producing poly(thiaheterohelicene)s with stiff intrachain helicity. In Part 2, both polythiophene derivatives and poly(para-phenylene vinylene) derivatives are discussed in terms of interchain helicity and the effect of chiral organisation on chiroptical properties. Subsequently, thienylene-based diblock copolymers are discussed in terms of formation of hierarchical superhelices. Finally, thienylene- and phenylene-based homopolymers and copolymers are discussed in terms of an interchain helically pi-stacked structure; reversible photoswitching of circularly polarised luminescence; and the evolution of RGB- and white-coloured, circularly polarised luminescence.