Zhang Huanhuan, Xu Lin, Lai Yuqing, Shi Tongfei
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Phys Chem Chem Phys. 2016 Jun 28;18(24):16310-6. doi: 10.1039/c6cp02447e. Epub 2016 Jun 2.
On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process.
在不润湿的固体基底上，聚合物薄膜的溶剂退火过程包括溶胀过程和去湿过程。由于难以同时对这两个过程进行原位分析，关于不润湿固体基底上聚合物薄膜溶剂退火过程的定量研究极为罕见。在本文中，我们设计了一种将椭圆偏振光谱法与光学显微镜相结合的实验方法，以实现同步原位研究。利用该方法，我们研究了溶胀膜结构对其在溶剂退火过程中去湿动力学的影响。结果表明，对于低分子量（Mw = 4.1 kg mol(-1)）的聚苯乙烯（PS）薄膜，在溶胀过程中丙酮分子可在PS薄膜与固体基底之间形成超薄富集层。丙酮富集层的存在解释了低分子量PS薄膜情况下的指数动力学行为。然而，在高分子量（Mw = 400 kg mol(-1)）的PS薄膜情况下未观察到丙酮富集层，并且在去湿过程中聚合物链的滑移效应起作用。
