Thermal stability of porous it-PMMA thin film obtained by the extraction of st-PMAA from it-PMMA/st-PMAA Stereocomplex with layer-by-layer assembly on a substrate

摘要

The functionality of porous isotactic (it) poly(methyl methacrylate) (PMMA) thin films, which were previously developed by the selective extraction of syndiotactic (st) poly(methacrylic acid) (PMAA) from the it-PMMA/st-PMAA stereocomplex thin film on a substrate using the layer-by-layer assembly method was investigated after thermal treatment (70, 80, and 90 °C) in water for 4 h. Quartz crystal microbalance analysis and infrared spectra measurements revealed that the st-PMAA incorporation ability of the porous it-PMMA thin film decreased in order at 80 and 90 °C, while there was no decrease observed at 70 °C. X-ray diffraction analysis also supported the thermal stability of the porosity at 70 °C, whereas two it-PMMA crystalline peaks (2θ = 9° and 14°) were generated during heating at 90 °C. The loss of the functionality of the it-PMMA thin film was thus shown to be due to crystallization, which was caused by the increase in polymerchain mobility during the heating process.