苯乙烯/甲基丙烯酸和苯乙烯/甲基丙烯酸(β-羟丙酯)嵌段共聚物的表面动态行为

通过测定表面动态接触角研究了两亲性的苯乙烯／甲基丙烯酸嵌段共聚物（ＰＳ ｂ ＰＭＡＡ）和苯乙烯／甲基丙烯酸（β 羟丙酯）嵌段共聚物（ＰＳ ｂ ＰＨＰＭＡ）的表面动态行为及温度、嵌段长度比等因素对其值的影响，讨论了聚合物表面当接触介质改变时链段或基团的再取向行为和表面性质

THE DYNAMIC BEHAVIOR OF SEGMENT/GROUP ON THE SURFACE OF BLOCK COPOLYMER

The reorientation of segments on the copolymer surface with change of immersion mediums have been investigated by dynamic contact angle (DCA) measurements. The samples are amphiphilic copolymer PS\|b\|PMAA or PS\|b\|PHPMA prepared by polymerized MAA or HPMA monomer with polystyrene macroinitiatior containing azo group. The results show that the reorientation of polar segments (PMAA or PHPMA segments) on the surface contribute to the contact angle hysteresis. The receding angle r is very sensityve to polarity and mobility of the segments on copolymer surface while advancing angle \-a remains at an approximate value for the samples on which surface PS segment enrichment took place, so the , a difference between advancing angle and receding angle, can be used as an indication of reorientation ability of segments and/or groups on the copolymer surface. The values of advancing angle or of receding angle measured in the second immersion cycle are same as that in the first, respectively, this reveals that the reorientation of segments and/or groups are reversible with the environmental change in the case of both PS\|b\|PMAA and PS\|b\|PHPMA. The results also show that the contact angle hysteresis depend on temperature of medium, i.e., the values of both \-a and decrease with increasing of temperature, and that dynamic behavior of the amphiphilic copolymers can be affect by ther ratio of sequence length (MPS/MPMAA or MPS/MPHPMA) in the macromolecular chain.\=