玻璃基板作用下高分子共混物薄膜相形态发展过程

INFLUENCE OF GLASS SUBSTRATE ON THE EVOLUTION OF PHASE MORPHOLOGY IN IMMISCIBLE POLYMER BLEND THIN FILMS

研究了玻璃基板作用下极性高聚物为低组分的共混物薄膜在退火条件下相形态的发展过程 .选用聚苯乙烯 (PS) 聚甲基丙烯酸甲酯 (PMMA)与聚苯乙烯 (PS) 聚ε 己内酯 (PCL)两个体系 ,在玻璃基板上Spin Coating成膜后退火 .由于共混物薄膜中极性相对较大的高聚物组分 (PMMA和PCL)相对于极性较小的PS组分对玻璃基板具有更好的润湿性 ,所以在上述的两个共混薄膜体系中其相形态分别显示PMMA和PCL在低组分比例下最终发展成为连续相 .利用扫描电镜以及元素分析很好地验证了以上的结论 ,并且对其机理进行了解释 .此外 ,改变PS的分子量与PCL共混 ,研究了组分粘度对薄膜相形态发展的影响 .结果表明 ,PS组分粘度越大 。

Two blend systems of polystyrene/poly ( methyl methacrylate) (PS/PMMA) and polystyrene/poly (epsilon-caprolactone) (PS/PCL) were studied by using their thin films prepared on a glass substrate by spin-coating from THF respectively. Phase contrast microscopy and scanning electron microscopy ( SEM) combined with elementary analysis were used to obtain information on the morphology in these thin films after heat treatment. It was found that PMMA-rich and PCL-rich phases were always continuous in thin films of either blends, even though the PMMA and PCL were the minor component in their blends. This should result from the better wetting abilities of PMMA and PCL on the glass substrate than PS in the blends. The spreading of PMMA or PCL phase in the blends on glass substrate during annealing induced the above results. The function of viscosity of the blend in the evolution of phase structure was also concerned via changing the molecular weight of PS component in the PS/PCL blend thin films.