聚苯乙烯/聚二甲基硅氧烷嵌段共聚物的表面形态研究

采用原子力显微镜(AFM)和透射电镜(TEM)研究了聚苯乙烯/聚二甲基硅氧烷嵌段共聚物(PS-b-PDMS)薄膜的相形态.结果表明,当采用甲苯作为溶剂,旋转涂膜的薄膜样品呈现网络状的形态分布在表面,而样品所对应的透射电镜照片中,PDMS相作为球状分布在PS的连续相中.退火温度对共聚物表面形态有一定的影响,当退火温度高于PDMS的玻璃化温度,表面中PDMS相增多.PS-b-PDMS嵌段共聚物的表面形态随着所用溶剂的变化而有所不同,当采用甲苯作为溶剂时,样品的PS相形成凹坑分布在PDMS的相区之中,而采用环己烷作为溶剂时,PS相作为突起分布在PDMS相区之中.另外,基底对共聚物薄膜表面形态的有较大的影响,当采用硅晶片作为基底时,样品中的PDMS相和PS相呈现近似平行于表面的层状结构.

STUDIES ON THE SURFACE MORPHOLOGY OF POLY(STYRENE-b-DIMETHYLSILOXANE) COPOLYMER THIN FILMS

Morphology of poly(styrene-block-dimethylsiloxane)(PS-b-PDMS) copolymer thin films was analyzed by atomic force microscopy(AFM) observation and transition electron microscopy(TEM) measurements.The asymmetric copolymer thin films spin-cast from toluene on mica presented a mesh-like structure,which was different from the sphericalop structure in the bulk.The annealing temperature affected the surface morphology of PS-b-PDMS copolymer thin films,PDMS microdomains at the surface were increased when the annealing temperature was higher than the PDMS glass transition temperature.The morphology of PS-b-PDMS copolymer thin films was different from solvent to solvent,for thin films spin-cast from toluene,the PS phase was pits in PDMS matrix.While the thin film spin-cast from cyclohexane solution exhibited an island-like structure,small separated PS phase appeared as protrusions over the macroscopically flat surface.The microphase structures of the PS-b-PDMS copolymer thin films were also strongly influenced by the different substrates,for an asymmetric block copolymer thin film,the PDMS and PS phases on silicon substrate presented lamellae structure parallel to the film surface.