Cooperative and Independent Effect of Modular Functionalization on Mesomorphic Performances and Microphase Separation of Well‐Designed Liquid Crystalline Diblock Copolymers

Abstract

Liquid crystalline block copolymers (LCBCPs) are promising for developing functional materials owing to assembly of better functionality. Taking advantage of difference in reactivity between alkynyl and vinyl over temperature during hydrosilylation, a series of LCBCPs with modular functionalization of block copolymers (BCPs) are reported by independently and site‐selectively attaching azobenzene moieties containing alkynyl (LC1) and Si‐H (LC2) terminals into well‐designed poly(styrene)‐block‐polybutadienes (PS‐b‐PBs) and poly(4‐vinylphenyldimethylsilane)‐block‐polybutadienes (PVPDMS‐b‐PBs) produced from living anionic polymerization (LAP). By the principle of modular functionalization, it is demonstrated that mono‐functionalized (PVPDMS‐g‐LC1)‐b‐PB and PS‐b‐(PB‐g‐LC2) not only maintain independence but also have cooperative contributions to bi‐functionalized (PVPDMS‐g‐LC1)‐b‐(PB‐g‐LC2) in terms of mesomorphic performances and microphase separation, which is evident from DSC and POM and identified by powder X‐ray diffractions. With the application of new principle of modular functionalization, local‐crosslinked liquid crystalline networks (LCNs) with controlled functionality are successfully synthesized, which show well‐controlled phase behaviors over molecular compositions.