Strategies for Tailoring LC-Functionalized Polymer: Probe Contribution of [Si–O–Si] versus [Si–C] Spacer to Thermal and Polarized Optical Performance “Driven by” Well-Designed Grafting Density and Precision in Flexible/Rigid Matrix

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• 作者：Li Han ; Hongwei Ma ; Yang Li ; Siqi Zhu ; Lincan Yang ; Rui Tan ; Pibo Liu ; Heyu Shen ; Wei Huang ; Xichen Gong
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：August 9, 2016
• 年：2016
• 卷：49
• 期：15
• 页码：5350-5365
• 全文大小：1376K
• 年卷期：0
• ISSN：1520-5835

文摘

A versatile strategy is highly desired to prepare well-designed side chain liquid crystal polymers (SCLCPs). Two rigid and topological SiH/Vinyl-functionalized polystyrenes (PSs), namely poly(4-vinylphenyldimethylsilane) (PVPDMS) and poly(4-vinylphenyl-1-butene) (PVSt), were synthesized via anionic polymerization (AP) and detailed; subsequently, Vinyl/SiH terminated LCs were treated with PVSt/PVPDMS via hydrosilylation to yield SCLCPs bearing [Si–O–Si]/[Si–C] spacers. Herein, well-designed grafting density, evaluated by ¹H NMR, was readily performed by the varying SiH to Vinyl feed mole ratio. The design systematically probes a cooperative effect of architectures on properties and allows for precision in flexible/rigid matrixes. Regardless, PB/PS systems with saturated addition displayed the best performances. Fundamentally, the study compared the dependence of polarized optical and thermal performances on [Si–O–Si] versus [Si–C] spacer, which submitted to be driven by grafting density, providing the first access to tailoring polymer. SCLCPs exhibited essentially constant S_mA, but inconsistent dynamic of spacer-induced contribution, in which ΔT was the same in complete addition as if nothing with spacer; surprisingly, followed by decreased grafting density, the decreasing trend in ΔT of [Si–O–Si] as spacer was fast, while that of [Si–C] was slow. This phenomenon was further confirmed by POM. Furthermore, [Si–O–Si] was desired to obtain lower T_g and applicable to the advantageous “decoupling effect”. Endeavor for tailoring SCLCPs and regulating devices, the appropriate spacer and grafting density advanced to an effective role.