原子力显微镜研究星形SEBS聚集体的表面形态变化

Changes of Surface Morphology of Star-like SEBS Block Copolymers Aggregate Studied by Atomic Force Microscopy

摘要:

采用原子力显微镜观察不同条件下星型苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物（简称SEBS）的甲苯溶液旋涂所得膜的表面形态，发现SEBS溶液质量浓度对膜表面形态起支配作用，随着SEBS质量浓度的增加，聚集体结构由单个大分子线团变为小球、二维网络以及连续膜；不同溶度参数的溶剂可以改变表面聚集体的尺寸，随着溶度参数的降低，旋涂膜表面聚集体的高度不断下降，溶剂更易渗透至聚合物大分子链间；随着热处理温度的提高，聚集体向完美小球颗粒转化；超声波处理后立即旋涂所得的膜表面形态上会出现大量气泡和气孔。对比相同条件下，线型SEBS与星型SEBS所得的AFM图可以发现，星型SEBS由于空间位阻的影响，分子链运动能力差，所以较线型SEBS聚集态的尺寸小。

Abstract:

The morphologies of films spin coated from star-like poly(styrene-b-ethylene/butylene-b-styrene) triblock copolymer (SEBS)/toluene solution onto a mica substrate were studied by atomic force microscopy (AFM). The results showed that the solution concentration determined the morphology of the aggregates, which displayed from single coil, spheres, network structure and continuous film with the increasing concentration. The size of aggregates could be influenced by the solubility of the solvent. With the increase of the solubility, the solvent could easily penetrate into the macromolecules, which resulted in the height of the aggregates on the surface of the film decreasing. The size of the aggregates could evolve to perfect spheres with heat treatment temperature. A lot of bubbles and pores could be observed at the morphology from the film spin coated immediately after ultrasonic treatment. Comparing the AFM patterns of linear SEBS (L-SEBS) with star-like SEBS (S-SEBS) under the same conditions, it was found that the size of aggregates of L-SEBS was smaller and the morphology was more difficult to change due to the steric hindrance and poor mobility of molecule chains of S-SEBS.