Visible Light Photoiniferter Polymerization for Dispersity Control in High Molecular Weight Polymers.

The synthesis of polymers with high molecular weights, controlled sequence, and tunable dispersities remains a challenge. A simple and effective visible-light controlled photoiniferter reversible addition-fragmentation chain transfer (RAFT) polymerization is reported here to realize this goal. Key to this strategy is the use of switchable RAFT agents (SRAs) to tune polymerization activities coupled with the inherent highly living nature of photoiniferter RAFT polymerization.

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

Liquid crystalline block copolymers (LCBCPs) are promising for developing functional materials owing to an assembly of better functionalities. Taking advantage of differences in reactivity between alkynyl and vinyl over temperature during hydrosilylation, a series of LCBCPs with modular functionalization of the block copolymers (BCPs) are reported by independently and site-selectively attaching azobenzene moieties containing alkynyl (LC ) and Si-H (LC ) 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-LC )-b-PB and PS-b-(PB-g-LC ) not only maintain independence but also have cooperative contributions to bi-functionalized (PVPDMS-g-LC )-b-(PB-g-LC ) in terms of mesomorphic performances and microphase separation, which is evident from differential scanning calorimetry (DSC) and polarized optical morphologies (POM) and identified by powder X-ray diffractions.