Fabrication of highly ordered microporous thin films by PS-b-PAA self-assembly and investigation of their tunable surface properties
Fabrication of highly ordered microporous thin films by PS-b-PAA self-assembly and investigation of their tunable surface properties
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DOI：
10.1039/b715520d
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发表时间：
2008-01-01
影响因子：
--
通讯作者：
Hu, Xiaoya
中科院分区：
文献类型：
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作者：
Wang, Chengyin;Mao, Yindao;Hu, Xiaoya
采用两亲性嵌段聚合物聚苯乙烯-b-聚丙烯酸（PS-b-PAA）自组装制备三维有序微孔薄膜。通过在高湿度条件下将PS-b-PAA四氢呋喃（THF）溶液浇铸到载玻片上来形成高度有序的微孔薄膜。冷凝水滴在空气-聚合物溶液界面上基于热毛细对流起牺牲模板的作用。研究了嵌段聚合物溶液浓度、环境相对湿度、溶剂性质、铺展体积和基底等关键影响因素，以控制膜的尺寸和调节膜的表面性能。光学接触角测量结果表明，薄膜在水溶液中的表面组成和润湿性发生了显著变化，薄膜表面的接触角从近疏水性变为超亲水性。研究了孔隙率和PAA离子化程度对上述性能的影响。膜的微孔直径决定了初始接触角，而PAA离子化程度决定了润湿行为的转变时间和最终接触角。微孔薄膜作为一种潜在的功能材料，在未来的应用中将发挥重要的作用。
A facile approach is presented to fabricate three-dimensional ordered microporous thin films by self-assembly via an amphiphilic block polymer, polystryene-b-polyacrylic acid (PS-b-PAA). The highly ordered microporous thin films were formed by casting a PS-b-PAA tetrahydrofuran (THF) solution onto a glass slide under high humidity conditions. The condensed water droplets act as sacrificial templates on the air - polymer solution interface based on thermocapillary convection. Some critical influencing factors, such as the concentration of the block polymer solution, the relative humidity of the atmosphere, the properties of the solvent, the spreading volume and the substrates, were investigated to control micropore size and tune film surface properties. The surface composition and wettability of the film were found to be dramatically changed in aqueous solution, and the contact angle of the film surface was interestingly reduced from nearly hydrophobic to super-hydrophilic, which was shown by optical contact angle measurements. The influence of porosity and the ionization degree of PAA on the above properties was investigated. Micropore diameters of the films determine the initial contact angle, while the PAA ionization degree determines the transformation time of the wettability behavior and the final contact angle. The microporous thin films, as potential functional materials, are expected to play an important role in future applications.