Controlled self-assembly of alkylated-π compounds for soft materials - Towards optical and optoelectronic applications

Organic and polymeric molecules based on pi-conjugated units represent an important class of components for optical and optoelectronic functionalized soft materials. Inspired by the innovative molecular design made by synthetic chemists, new functions and applications of pi-conjugated molecules are continuously emerging. However, a challenge that remains is to soften these molecules. Alkylation is a commonly employed synthetic strategy to achieve functionalization in order to improve processability, i.e., solubility in volatile solvents, for better utilization in the rapidly-developing field of organic electronics. In addition it is recognized as a powerful strategy to tune the interaction among the pi-conjugated moieties. In a different interpretation of alkylation, alkylated-pi compounds can be viewed as a class of hydrophobic amphiphiles, since the rigid pi-conjugated moiety and flexible alkyl chains are intrinsically immiscible. Recent studies have shown that such compounds can form a variety of self-organized solid and thermotropic liquid crystalline structures as well as nonassembled liquid forms depending upon the position, number and kinds of attached alkyl chains. Here, we present a brief overview of recent developments of alkylated-pi chemistry, with an emphasis on the relationships between molecular design, self-assembly behavior and applications in optical and optoelectronic devices. We hope this review can serve as a guide and reference for people working in different research areas, including self-assembly and colloid sciences, synthetic and materials chemistry was well as organic electronics. (C) 2014 Elsevier Ltd. All rights reserved.