Modulation of thermodynamic and kinetic inverted phase behavior of block copolymers by inorganic polyoxometalates
Modulation of thermodynamic and kinetic inverted phase behavior of block copolymers by inorganic polyoxometalates
复制标题
无机多金属氧酸盐调节嵌段共聚物的热力学和动力学反相行为
DOI：
10.1039/c9sm01041f
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发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Zhang Jie
中科院分区：
文献类型：
--
作者：
Tan Junyan;Liu Zhiyao;Wang Rong;Zhou Yue;Xie Siyu;Li Baohui;Wan Xinhua;Zhang Jie
在DMF中，Keggin多金属氧酸盐(POM)H3PW12O40(PW)与聚(苯乙烯-嵌段-2-乙烯基吡啶)(PS-b-P2VP)形成静电络合，通过溶剂挥发实现有序微相分离。用SAXS和透射电子显微镜系统地研究了PS-b-P2VP/PW嵌段共聚物的相行为，考察了POM含量和嵌段共聚物相对分子质量的影响。计算模拟也揭示了与实验结果相同的相变序列。随着POM含量的增加，低相对分子质量的PS-b-P2VP/PW复合材料由片状相(LAM)转变为六方柱状相(HEX)，最后转变为球形相(SPH)。出乎意料的是，高相对分子质量的PS-b-P2VP/PW络合物倾向于形成动力学捕获中间相(倒置HEX)。通过模拟浓缩二甲基甲酰胺溶液中的不对称溶胀最终形成体相中的动力学捕获纳米结构，提出了反相的形成机理。
The Keggin polyoxometalates (POM) H3PW12O40 (PW) electrostatically complexed with poly(styrene-block-2-vinyl pyridine) (PS-b-P2VP) in DMF, and ordered microphase separation occurred through solvent evaporation. The phase behaviors of PS-b-P2VP/PW in bulk were systematically investigated by using SAXS and TEM to discover the effect of POM content and molecular weight of the block copolymers. Computational simulation was also performed to reveal the same phase transition sequence as the experimental results. As the POM content increases, the PS-b-P2VP/PW complex with a low molecular weight changed from lamellar phase (LAM) to hexagonal cylindrical phase (HEX), and finally transited into spherical phase (SPH). Unexpectedly, PS-b-P2VP/PW complexes with a high molecular weight were inclined to form a kinetic-trapped intermediate phase (inverted HEX). The mechanism of formation of inverted phases was proposed based on simulation that asymmetric swelling in the concentrated DMF solution would result in the ultimate kinetic-trapped nanostructure in the bulk.