溶剂诱导嵌段共聚物PS-b-PEO方形片层的形貌转变  

Solvent vapor induced morphology transition of square slice obtained from PS-b-PEO solution

作　　者：毛虎[1] 李宏飞[2] 蒋世春[1] 

机构地区：[1]天津大学材料科学与工程学院,天津300072 [2]中国科学院长春应用化学研究所高分子物理与化学国家重点实验室,吉林长春130022

出　　处：《分子科学学报》2012年第2期109-114,共6页Journal of Molecular Science

基　　金：国家自然科学基金资助项目(20974077;51173130).

摘　　要：嵌段共聚物聚苯乙烯-b-聚氧化乙烯(PS-b-PEO)甲苯溶液在室温下陈化2个月可形成中间是PEO单晶上下表面为PS具有"三明治"结构的方形片层,并且既能形成单层方形片层,也能形成多层方形片层.采用透射电子显微镜手段观察了这种结构在不同水含量的水/甲苯混合溶剂蒸汽诱导后形成的结构形貌.结果证明在甲苯和水蒸汽中,方形片层结构均能稳定存在,不能进行结构重构;而随着混合蒸汽中水含量的增加,单晶溶解、消失,在甲苯和水的共同作用下,可通过结构重构形成新的垂直或平行于表面的柱状相结构.In this paper,the structures of polystyrene-b-poly（ethylene oxide）（PS-b-PEO） square slice formed in toluene solution and transformed in vapor of water/toluene mixtures were investigated via TEM.The square slice can be obtained from PS-b-PEO/toluene solution after ageing for 2 months at room temperature,which is possessed of ＂sandwich structure＂ constructed from a PEO single crystal and covered with two tethered PS block layers on the up and down crystal basal surfaces.Not only the single layer square slices,but also the multilayer square slices were both obtained.The PEO single crystal could not be swelled or solvated in toluene vapor and in water vapor,for the poor solubility of toluene for PEO and the barrier of PS layer toward water.Therefore,there were no morphology transitions of the square slice in the two kinds of vapor.With increasing of the water fraction in water/toluene mixtures,the square slices transformed to cylindrical microdomains.The structure rearrangement is due to the dissolution of PEO single crystal and the microphase separation of the block copolymer.The content of water in the mixed solvent is the key factor to the formation of the vapor induced structures.The PEO single crystal could not be solvated in the vapor of mixed solvent with 10% water.So there would no further phase transition.When the water in the mixtures were increased to 20% and 50%,the layer with PEO single crystal could be solvated and rearranged to cylindrical microdomains with perpendicular or parallel to the surface.

关 键 词：PS-b-PEO嵌段共聚物 方形片层结构 溶剂诱导 结构重构 

分 类 号：O626[理学—有机化学]