Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of the Education Ministry, Zhejiang Sci-Tech University, Hangzhou, China.
Langmuir. 2012 Mar 6;28(9):4283-92. doi: 10.1021/la300119n. Epub 2012 Feb 27.
In this paper, a series of poly(styrene-b-isoprene-b-styrene) triblock copolymers (SIS), with different chemical components, was synthesized by anionic polymerization. The relationships between surface structures of these block copolymers and their stick-slip phenomena were investigated. There is a transition from stick-slip to a closely smooth motion for the SIS films with increasing PS content; the patterns almost vanish and the three-phase line appears to move overall smoothly on the film surface. The results show that the observed stick-slip pattern is strongly dependent on surface viscoelasticity. The jumping angle Δθ, which is defined as θ(1) - θ(2) (when a higher limit to θ(1) is obtained, the triple line "jumps" from θ(1) to θ(2) with increases in drop volume), was employed to scale the stick-slip behavior on various SIS film surfaces. Scanning force microscopy/atomic force microscopy (AFM) and sum frequency generation methods were used to investigate the surface structures of the films and the contributions of various possible factors to the observed stick-slip behavior. It was found that there is a linear relationship between jumping angle Δθ and the slope of the approach curve obtained from AFM force measurement. This means that the stick-slip behavior may be attributed mainly to surface viscoelasticity for SIS block copolymers. The measurement of jumping angle Δθ may be a valuable method for studying surface structure relaxation of polymer films.
本文采用阴离子聚合的方法合成了一系列具有不同化学组成的聚苯乙烯-异戊二烯-聚苯乙烯三嵌段共聚物（SIS）。研究了这些嵌段共聚物的表面结构与其粘滑现象之间的关系。随着 PS 含量的增加，SIS 薄膜的粘滑现象从粘滑转变为几乎平滑的运动；图案几乎消失，三相线似乎在薄膜表面整体平滑地移动。结果表明，观察到的粘滑模式强烈依赖于表面粘弹性。跳跃角Δθ（当获得θ(1)的上限时，随着液滴体积的增加，三线从θ(1)“跳跃”到θ(2)）被用来对各种 SIS 薄膜表面上的粘滑行为进行标度。扫描力显微镜/原子力显微镜（AFM）和和频发生方法被用来研究薄膜的表面结构以及各种可能因素对观察到的粘滑行为的贡献。发现跳跃角Δθ与 AFM 力测量得到的接近曲线的斜率之间存在线性关系。这意味着 SIS 嵌段共聚物的粘滑行为可能主要归因于表面粘弹性。跳跃角Δθ的测量可能是研究聚合物薄膜表面结构弛豫的一种有价值的方法。
