摘要
Polymeric monoliths are of great interest in a variety of applications.A new gelation approach to produce a mechanically stable polystyrene(PS)gel directly from its microemulsion is reported.To produce a PS gel,the as-prepared microemulsion is first demulsified by adding selected watermiscible organic solvents.The small PS latex particles liberated from the surfactant are assembled into a piece of bulk material at an appropriate temperature with a high degree of entanglement of the polymer chains.It is found that the d2 T/ηvalue is an important parameter to evaluate the gelation ability of the organic solvents and helps determine the gelation conditions.Finally,PS monoliths are obtained by capillary drying and their pore structures can be effectively tuned by changing the gelation time and the amount of solvent exchanged with water.This allows the controlled preparation of bulk PS artefacts with densities in the range of 0.06 to 1.14 g cm^(-3).This simple method of PS monolith production avoids the use of shaping tools or chemical templates,needs less energy,and is a promising alternative approach to design either integrated porous or compact polymer materials.
本文利用一种新的聚苯乙烯(PS)微乳液的凝胶化现象,制备了结构稳定的PS凝胶,并通过可控的毛细收缩过程获得了具有不同孔隙结构的PS块体.对PS微乳液的凝胶化机制的系统研究表明,在PS微乳液中加入适量特定的水溶性有机溶剂后,可实现PS微乳液的破乳,PS乳胶粒子周围的表面活性剂完全解吸附,并自发团聚成二次颗粒,在适当温度条件下可通过分子链缠结组装形成三维多孔凝胶.不同溶剂实现PS微乳液凝胶化的能力可以通过d2T/η参数的大小衡量和评估.通过进一步调整成胶时间与溶剂置换程度,PS凝胶可在后续的干燥过程中实现不同程度的收缩,从而得到密度范围在0.06–1.14 g cm^(-3)的多孔或致密PS块体.这种PS凝胶化策略是一种简单高效的PS成型方法,避免了成型设备、模板、成孔剂以及大量表面活性剂的应用,有望成为制备功能高分子聚合物块体材料的新方法.
作者
Dewang Li
Yaqian Deng
Jingyi Xia
Zhitan Wu
Tongxin Shang
Pei Li
Junwei Han
Ying Tao
Quan-Hong Yang
Nanoyang Group
State Key Laboratory of Chemical Engineering
School of Chemical Engineering and Technology
Tianjin University
Tianjin
李德望;邓亚茜;夏静怡;吴志坦;尚童鑫;李培;韩俊伟;陶莹;杨全红;Nanoyang Group;State Key Laboratory of Chemical Engineering;School of Chemical Engineering and Technology;Tianjin University;Tianjin(Nanoyang Group,State Key Laboratory of Chemical Engineering,School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China;Shenzhen Key Laboratory for Graphene-Based Materials,Engineering Laboratory for Functionalized Carbon Materials,Graduate School at Shenzhen,Tsinghua University,Shenzhen 518055,China;Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Fuzhou 350207,China)
基金
financially supported by the National Science Fund for Distinguished Young Scholars of China(51525204)
the National Natural Science Foundation of China(51702229)。
