柱状相聚苯乙烯-b-聚乳酸的合成及引导组装

doi:10.11944/j.issn.1000-0518.2018.12.180075

摘要/Abstract

摘要：

设计并合成了2种柱状相结构的聚苯乙烯-b-聚乳酸(PS-b-PLA)两嵌段共聚物,并表征了它们在化学图案上的引导自组装行为。在辛酸亚锡(Sn(Oct)₂)催化下,采用羟基官能化的聚苯乙烯(PS-OH)大分子引发剂分别引发外消旋丙交酯(rac-LA)和左旋丙交酯(L-LA)开环聚合,制备了两个相对分子质量相近但构型不同的PS-b-PLA:PS-b-PDLLA和PS-b-PLLA。通过核磁共振波谱仪(NMR)、凝胶渗透色谱仪(GPC)、示差扫描量热仪(DSC)、热重分析仪(TGA)、小角X射线衍射仪(SAXS)等测试手段对两个嵌段共聚物的性质进行了表征。然后,将PS-b-PDLLA和PS-b-PLLA薄膜在六方点阵化学图案模板上加热引导自组装,得到长程有序排列的六方柱状相结构。相对于柱状相的PS-b-PLLA,柱状相的PS-b-PDLLA具有较大的拉伸比例,可以在更大的周期范围内组装出规整的六方结构。这一结果与层状相PS-b-PDLLA和PS-b-PLLA薄膜在线性化学图案上组装的结果相似。

关键词: 聚苯乙烯-b-聚乳酸, 两嵌段共聚物, 引导组装, 化学图案

Abstract:

Two cylinder-forming poly(styrene-b-lactide)s, poly(styrene-b-D,L-lactide)(PS-b-PDLLA) and poly(styrene-b-L-lactide))(PS-b-PLLA), with similar domain sizes(L_O) were synthesized using ring opening polymerization(ROP) of lactide monomers from hydroxy-terminated polystyrene(PS-OH) with zinc octoate(Sn(Oct)₂) as the catalyst and characterized by nuclear magnetic resonance spectroscopy(NMR), gel permeation chromatography(GPC), differential scanning calorimetry(DSC), thermal gravimetric analyzer(TGA) and small-angle X-ray scattering(SAXS). Thin films of PS-b-PDLLA and PS-b-PLLA were directed to assemble on hexagonal arrays of spot chemical patterns with a range of pattern periods(L_S) under thermal annealing. SEM analysis of the two assembled films revealed that long-range ordered perpendicularly-oriented hexagonal-array cylinders were obtained in both films. The range of L_S window for defect-free assembly of perpendicular cylinders was larger in PS-b-PDLLA films than that in PS-b-PLLA films, which is similar to the assembly behavior of lamellar-forming PS-b-PLA on stripe chemical patterns.

Key words: poly(styrene-b-lactide), block copolymers, directed self-assembly, chemical pattern

张潇飒, 季生象. 柱状相聚苯乙烯-b-聚乳酸的合成及引导组装[J]. 应用化学, 2018, 35(12): 1420-1426.

ZHANG Xiaosa, JI Shengxiang. Synthesis and Directed Self-assembly of Cylinder-Forming Poly(styrene-b-lactide) Block Copolymers[J]. Chinese Journal of Applied Chemistry, 2018, 35(12): 1420-1426.

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