聚合物熔体膜在基体表面的润湿和铺展行为

The Wetting and Dewetting Properties of Polymer Thin Films on Substrates

聚合物熔体膜在基体表面上的润湿和铺展行为受铺展系数和 Hamaker常数影响。对于不能在基体表面上铺展的聚合物膜 ,当处于其玻璃化温度以上时 ,聚合物熔体膜将破裂 ,出现非连续区域。随着体系处于聚合物玻璃化温度以上时间的延长 ,非连续部分尺寸不断增长 ,增长速率与表面张力、聚合物粘度、聚合物液滴在基体表面的平衡接触角等因素有关 ,平衡后聚合物以液滴的形式在基体表面稳定存在。将带功能端基聚合物加入不能在基体表面上铺展的聚合物中 ,通过修饰聚合物与基体界面或改变聚合物熔体膜的表面张力 ,可以使原来不能在基体表面铺展的聚合物保持稳定。本文综述了聚合物熔体膜的铺展和润湿动力学研究进展 ,并归纳了使聚合物熔体膜稳定的方法。

The key parameters which control the wetting and dewetting properties of polymer thin films on substrates are Hamarker constant(A) and spreading coefficient(S). If the polymer films are formed on non\|wettable substrates, they should exist in a metastable state. In this case, when the films are annealed at temperature above their glass transition temperature, dewetting will take place. The dewetting velocity is mainly determined by the surface tension, vicosity of polymer melt and the equilibrium contact angle of polymer droplet on the substrate. For the systems of polymer films on non\|wettable substrates, the dewetting dynamics of polymer films will be obviously changed and the films can become stable under special conditions like adding end functional polymer to the system. In this paper, the wetting and dewetting properties of polymer thin films on substrates are reviewed.