Order from disorder: Directed assembly of alkyl-π functional molecular liquids

Controlled self-assembly of π-conjugated molecules is a widely accepted approach to optimizing the performance of organic optoelectronics. In particular, directed assembly delivers precisely organized π-conjugated units in response to external stimuli. The attachment of branched alkyl chains not only modulates these assembly processes, but also isolates the π-core as observed in alkyl-π functional molecular liquids (FMLs). This review highlights recent advances in alkyl-π FMLs, their molecular design principle, and the methodologies to achieve their directed assembly by chemical additives and physical stimuli. It also presents how the disorder-to-order transition in alkyl-π FMLs leads to altered photoluminescence and other inherent benefits of these stimuli-driven assembled structures, which comprise a new paradigm in the field of stimuli-responsive soft materials and their application in soft electronics.