新型对称性两亲含硅聚合物的合成与界面性能

基于原子转移自由基聚合(ATRP)机理,以二甲基一氯硅烷封端的烯丙基-聚乙二醇为起始剂,甲基丙烯酸乙酯(EMA)为单体,通过控制反应温度,合成了一系列聚合度(DP_(NMR))分别为0. 74,1. 67和3. 07的新型对称性两亲含硅共聚物(PEMA-b-Si-PEG-Si-b-PEMA),并评价了该共聚物在氯仿/水界面的界面活性和吸附行为。结果表明:该类聚合物可以有效降低氯仿/水界面张力,具有最短PEMA链的聚合物可将氯仿/水界面张力从32 m N/m降低至约23 m N/m。动态界面张力分析表明:低浓度的共聚物在吸附的初始阶段符合扩散控制,且较短的PEMA链段有利于产生较快的扩散速率。平衡界面张力分析表明:随着界面浓度的增加,共聚物将表现出多种吸附状态,其吸附状态的数量以及聚合物在界面的偏摩尔面积将随着PEMA链长度的增加而增加。

Synthesis and interfacial properties of novel symmetric amphiphilic silicon-containing polymers

A series of novel symmetric amphiphilic silicon-containing polymers (PEMA-b-Si- PEG-Si-b-PEMA) were prepared by atom transfer radical polymerization (ATRP), which was achieved by the polymerization of ethyl methacrylate (EMA) with dimethylchlorosilane-terminated allyl-substituted poly(ethylene glycol). The DPNMR was 0.74, 1.67 and 3.07 as controlled by the reaction temperature. The interfacial activity and adsorption behavior of the polymers at chloroform/water interface were evaluated. The results show that the polymers can effectively reduce the chloroform-water interfacial tension, and the polymer with the shortest PEMA chain can reduce the chloroform-water interfacial tension from 32 mN/m to approximately 23 mN/m. The analysis of dynamic interfacial tension indicates that the adsorption at the initial stage is diffusion-controlled at lower concentrations of the polymer, and the shorter PEMA chain facilitates a faster diffusion rate. Equilibrium adsorption analysis reveals that the polymer exhibits various adsorption states as the interface coverage is increased, and the number of adsorption states and the range of partial molar area increase with the increase of PEMA chain length.