Laponite在高聚物/粘土温敏片状结构胶中的定向排列

Oriented Laponite in the Temperature-responsive Microsheet Gel from Copolymer/Clay Hybrids

有机/无机杂化材料由于其特性长期以来一直是人们研究的热点。阳离子聚(N-异丙基丙烯酰胺)接枝共聚物(PDMA+-PNIPAm)的浓溶液具有温度响应性的可逆凝胶-溶液相转变。研究发现,人造粘土Laponite分散在接枝共聚物水溶液中,两组分间自组装生成微米级的片状结构胶。偏光显微镜观察到Laponite粘土粒子在片状结构中取向排列,形成薄片的经络。微米级片状结构胶在水中均匀分散,自然晾干的过程中片状结构胶之间再次交联,形成不可再分散的杂化水凝胶。水凝胶具有良好的吸水性,吸水后的水凝胶具有灵敏的温度刺激性收缩或舒张。

Organic-inorganic hybrids with the new properties are attracting considerable attention in the literature.Cationic PNIPAm (N-isopropylacrylamide) graft copolymers in concentrated solution transform into reversible gel-solution with temperature changing.Recent studies show that hybrid micro-sheets are formed by self-assembly of laponite and Cationic PNIPAm graft copolymers in aqueous solution.It was found that laponite particles directed self-assembly in hybrids and anisotropic micro-sheets formed with laponite acting as skeletons under polarizing microscope.Aqueous dispersions of the micro-sheets spontaneously formed gels when dried at room temperature.The forming gel has strong water-sucking ability and stable thermoresponsive hybrid hydrogels demonstrate sensitive contraction or expansion with changing temperature.