Dispersity and architecture driven self-assembly and confined crystallization of symmetric branched block copolymers
Dispersity and architecture driven self-assembly and confined crystallization of symmetric branched block copolymers
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DOI：
10.1039/c9py01173k
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发表时间：
2019-10-21
影响因子：
4.6
通讯作者：
Hillmyer, Marc A.
中科院分区：
文献类型：
--
作者：
Pitet, Louis M.;Chamberlain, Bradley M.;Hillmyer, Marc A.
研究了线型、H型和芳香型三嵌段共聚物的大分子构型对三嵌段共聚物形态和热性能的影响。通过透射电子显微镜(TEM)和小角X射线散射(SAXS)观察到的微观形态差异表明，链状拓扑结构显著影响微相分离微区的界面曲率。与传统的低分散度线性三嵌段相比，支化的分子结构和摩尔质量分散度(D)导致传统的平衡微相分离结构之间的相界显著地向末端嵌段的较高体积分数(即聚乳酸)移动。研究还发现，大分子拓扑结构强烈影响半结晶PCOE块中同相成核与非均相成核的程度。主体相行为分析的结果表明，通过合成简单的路线利用不同的结构来微调嵌段聚合物的性质的能力。
The effect of macromolecular architecture on the morphology and thermal characteristics of triblock copolymers was evaluated for linear, H-shaped, and arachnearm architectures with poly(cis-cyclooctene) (PCOE) midblocks flanked with arms of poly(d,l-lactide) (PLA). Chain topology was found to significantly influence the interfacial curvature of the microphase separated domains, as implicated by morphological differences observed by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The branched molecular architectures and molar mass dispersities (D) of the triblock polymers examined here resulted in a significant shift in the phase boundaries between conventional equilibrium microphase separated structures to higher volume fractions of the end blocks (i.e., PLA) as compared to conventional low dispersity linear triblocks. Macromolecular topology was also found to strongly influence the extent of homo- vs. heterogeneous nucleation in the semi-crystalline PCOE block. The culmination of the bulk phase behavior analysis demonstrates the ability to fine-tune the properties of the block polymers by exploiting different architectures through a synthetically straightforward route.