【作者】 刘梅； 王茜； 赵兴娟； 刘洪国；

【Author】 Mei Liu;Qian Wang;Xingjuan Zhao;Hong-Guo Liu;Key Laboratory for Colloid and Interface Chemistry of Education Ministry,Shandong University;

【机构】 山东大学胶体与界面化学教育部重点实验室；

【摘要】 双亲嵌段共聚物具有丰富的自组装行为,在体相、溶液中、薄膜中及气/液界面上可形成多种微纳米结构。但其在液/液界面上的吸附和自组装行为的研究则较少。近年来,我们对双亲嵌段共聚物在液/液界面上的吸附和自组装进行了一些探讨,并发展了几种组装聚合物基复合微纳米结构的方法。首先研究了嵌段共聚物在互不相溶的两液相构成的液/液界面上的吸附和自组装行为,发现聚合物的分子结构、油相中聚合物的浓度和水相中无机组分的浓度等因素对聚合物分子的界面吸附和自组装行为有很大影响。在不同条件下,双亲嵌段共聚物可在液/液界面上形成泡沫状、蜂巢状及网状结构。其次,改进了界面组装的方式,以两种有机溶剂的混合溶液作为油相,使其与水溶液形成液/液界面。在这两种有机溶剂中,一种为极性较弱的溶剂,如氯仿;另一种为极性较强且可与水混溶的溶剂,如DMF、THF、丙酮等。当液/液界面形成后,由于有与水相混溶的有机溶剂的存在,发生通过界面的物质转移:水溶液向油相,有机溶液向水相迁移。借助于ouzo效应,两相分别形成了乳液。对于双亲性较为均衡的嵌段共聚物,如PS-b-PAA-b-PS,则可以稳定下相油包水乳液中的液滴,使聚合物与无机组分以液滴为模板进行组装,并最终在液/液界面上吸附而形成复合泡沫薄膜;对于疏水性较强的嵌段共聚物,如PS-b-P2VP,则聚合物随极性溶剂迁移到上相后,由于极性溶剂与水相混溶而使聚合物在混合水溶液中发生自组装形成胶束和囊泡等聚集体。这些聚集体最终在气/液界面上吸附,形成具有不同形貌和结构的复合薄膜。更多还原

【Abstract】 Amphiphilic block copolymers exhibit abundant self-assembly behaviors in bulk,in solutions,in spin-coating and casting thin films and at the air/water interface.They can form various ordered assemblies due to their microphase separation and micellization properties.Recently,we have investigated adsorption and self-assembly behaviors of some amphiphilic block copolymers at the liquid/liquid interface,and developed a new method to fabricate composite films with various morphologies and structures.We found that block copolymers formed various microstructures,including foam,honeycomblike structure,and networks at the liquid/liquid interfaces between two immiscible aqueous and oil phases,which were influenced greatly by experimental conditions,such as inorganic species,polymer structures,concentrations,and so on.When a mixed organic solution that contains strong polar and water-miscible species,such as DMF was used as the oil phase,W/O and O/W emulsions formed immediately in the lower and upper phases,respectively due to the mass transfer across the interface arising from the so called "ouzo effect".If the block copolymer has moderate amphiphilicity,the formed W/O emulsion in the lower phase are stable enough,and the polymer molecules adsorb around the water droplets and interact with the inorganic species in the droplets to form microcapsules.These microcapsules adsorb at the liquid/liquid interface to form a foam film at last.If the block copolymer has more hydrophobicity,they can not stabilize the W/O emulsion formed in the lower phase.On the contrary,they enter into the upper aqueous phase with the water-miscible solvent and self-assemble into micelles,vesicles or microcapsules due to the diffusion of the strong polar solvent into water.These assemblies adsorb at the air/water interface and form thin films at last.The morphologies and structures of these films are also affected by experimental conditions and can be tuned facilely.更多还原