Macromolecular Engineering on Triphenylene Based Discotic Side-chain Liquid Crystalline Polymers

作者：Mu, Bin; Wu, Bin; Chen, Dong-zhong^*

来源：Acta Polymerica Sinica, 2017, (10): 1574-1590.

DOI：10.11777/j.issn1000-3304.2017.17125

• Discotic side-chain liquid crystalline polymer
• Molecular weight effect
• Positive coupling effect
• Controlled synthesis
• High charge carrier mobility

Discotic side-chain liquid crystalline polymers (SCLCPs) are expected to develop into a new generation of flexible organic polymer as advanced optoelectronic functional materials, by combining the order and optoelectronic properties of discotic liquid crystals and the flexibility and excellent film-forming advantages of polymers. This article introduces the research progress of discotic SCLCPs. Based mainly on the research progress of our group, we focus on summarizing and commenting the controlled preparation of triphenylene (TP) based discotic SCLCPs through controlled/living radical polymerization, as well as expounding molecular weight (MW) effect and spacer length influence of discotic SCLCPs. We have successfully realized the controllable preparation of well-defined TP polyacrylate discotic SCLCPs via reversible addition-fragmentation chain-transfer (RAFT) polymerization for the first time. Then, discrete columnar stack (DCS) based intracolumnar stacking mode has been proposed accounting for the remarkable MW effect at degree of polymerization (DP) around 20. Particularly, positive coupling effect (PCE) is disclosed for discotic SCLCPs, that is, the strong coupling effect of the shorter spacers is more favorable for the formation of ordered columnar mesophases, in striking contrast with the renowned classical longer flexible spacer decoupling principle derived from calamitic SCLCPs, complementing the missing theoretical short board. The polyacrylate SCLCPs with butoxy TP side-groups have been designed and synthesized based on these principles, showing a very high charge carrier mobility of one to two orders of magnitude higher than those reported as measured by the time-of-flight (TOF) technique. Our preliminary macromolecular engineering practices are further extended into the field of inducing assembly to form homochiral helical superstructures of electron donor-acceptor polymer complexes by doping with chiral guest acceptors, as well as controlled preparation and properties studies of cyclic polymers and block copolymers. The controllable preparation of discotic SCLCPs and the elucidation of some fundamental issues, such as MW effect and the spacer length influence, will provide guidance for the rational design and controlled synthesis of such kind of important organic polymer semiconducting materials, and lay a foundation for boosting their optoelectronic device applications.

• 出版日期2017-10-20
• 单位南京大学