文献类型：期刊文献

英文题名：Lock/Unlock Mechanism of Solvent-Responsive Binary Polymer Brushes: Density Functional Theory Approach

作者：Xu, Yuli[1,2];Chen, Xueqian[3];Han, Xia[1,2];Xu, Shouhong[1,2];Liu, Honglai[1,2];Hu, Ying[1,2]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem & Engn, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China;[3]E China Univ Sci & Technol, Dept Phys, Shanghai 200237, Peoples R China

年份：2013

卷号：29

期号：16

起止页码：4988

外文期刊名：LANGMUIR

收录：;EI(收录号：20131816292620);WOS:【SCI-EXPANDED(收录号:WOS:000318143600008)】；

基金：This work is supported by the National Basic Research Program of China (2013CB733501), the National Natural Science Foundation of China (project nos. 21176065 and 21076071), the 111 Project of the Ministry of Education of China (no. B08021), and Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Chains - Dendrimers - Density functional theory - Locks (fasteners)

摘要：A density functional theory (DFT) approach based on a weighted density approximation has been employed to study the perpendicular microphase separation of symmetric binary polymer brushes with weak a incompatibility in explicit solvents with different selectivities. Characterized by the relation between the grand potential and vertical structures (including nonlayered and layered structures), a dry binary brush can be categorized as W-type or U-type according to whether the characteristic relation contains a structure that undergoes spontaneous symmetry breaking. A W-type brush can memorize the selectivity of the induced solvent in one of its two layered structures after the removal of solvent, which can be seen as a kind of lock state with the nonselective solvent used as its key to unlock. A U-type brush is lockless but can adapt to the environment without the nonselective solvent's triggering. Also, the boundary described in chain-length-incompatibility space is investigated by the DFT approach, which also verifies that the spontaneous symmetry breaking of the W-type brush originates from the molecular contributions to asymmetry, such as the enthalpic contribution of incompatibility and the entropic contribution of chain connectivity.