溶剂对SEBS/PMMA共混物薄膜形态的影响

采用原子力显微镜研究了聚（苯乙烯嵌-乙烯／丁烯嵌-苯乙烯）（SEBS）和聚甲基丙烯酸甲酯（PMMA）共混物不同溶剂旋转涂膜的表面形态和相分离行为。结果表明，用共混物的氯仿溶液旋转涂膜，可见明显的共混物的宏观相分离和SEBS的微观相分离形态。改变选择性溶剂可使旋涂膜具有不同的均匀度和形态结构，其相区的尺寸和形状相差甚大，有海岛型、网状、双连续状结构。AFM显示用环己烷／丁酮混合溶剂旋转涂膜，共混物的相分离最为彻底；用选择性溶剂氯仿时次之，但有明显的相分离；对SEBS和PMMA均无选择性的单一溶剂或混合溶剂则无明显相分离。

Solvent Effect on the Surface Morphology of SEBS/PMMA Blend Films

The influences of solvents used for spin-coating on the surface morphology and phase seperation behavior of poly(styrene-block-ethylene/butylene-block-styrene)(SEBS)/poly(methyl methacrylate)(PMMA) blend films were investigated by AFM.An evident macro-phase separation between SEBS and PMMA blend and a micro-phase separation in SEBS copolymer were observed simultaneously in the blend film spin-coated from chloroform solvent.Different solvents can control the film morphologies with distinct domain shape and domain size.Island-sea morphology,mesh-like morphology and co-continuous morphology were obtained with solvents used.The extent of phase-separation for cyclohexane/MEK spin-coated film was deeper than that for the other solvents.In the case of the chloroform spin-coated,the extending PMMA chains would be beneficial to the phase-separation,but the extent was confined by the coils of collapsed SEBS chains.In the case of those films spin-coated from 1,2-dichloroethane and n-heptane/acetone solvents,no notable phase-separation was observed.