Thermally stable and solvent resistant honeycomb structured polystyrene films via photochemical cross-linking

Abstract

In this article, a facile static breath-figure (BF) method to prepare highly ordered polystyrene (PS) thin films was reported. The static process was robust and tolerated more variability in casting conditions, although non-polar linear PS was not believed to be a good candidate for the BF technique. In the following UV irradiation, not only were the microporous structures well preserved, but also thermal and chemical resistance of the films was significantly improved due to the cross-linkage. Moreover, the surface wettability was changed from hydrophobicity to hydrophilicity. The cross-linked honeycomb structured PS films became resistant to a wide range of organic solvents and thermally stable up to 250 °C, an increase of more than 150 K as compared to the uncross-linked films. The simple cross-linking operation opened the door to facilely fabricate robust and low-cost microporous polymer films.