Specific recognition of syndiotactic poly(methacrylic acid) in porous isotactic poly(methyl methacrylate) thin films based on the effects of stereoregularity, temperature, and solvent

摘要

The effects of stereoregularity, temperature, and solvent on the specific recognition of syndiotactic (st)-poly(methacrylic acid) (PMAA) In macromolecularly porous isotactic (it)-poly(methyl methacrylate) films were investigated to give important insights into the regularity and stability of nanospaces in the it-PMMA films as well as template polymerization. The porous it-PMMA films were fabricated on quartz crystal microbalance (QCM) substrates via the layer-by-layer (LbL) assembly of it-PMMA/st-PMAA, plus the st-PMAA extraction from the assembly. QCM analysis and infrared spectroscopy revealed the first case of stereocomplex formation using st-PMAA with lower stereoregularity (rr= 73%) in the LbL films, while st-PMAA obtained with conventional free radical polymerization (rr = 62%) was barely incorporated into the porous it-PMMA films. The maximum st-PMAA incorporation increased from 25 to 40°C, but there were almost no difference between 40 and 55°C, indicating that the it-PMMA crystallization would also be accelerated with increasing temperature. The studies on st-PMAA incorporation with various complexing solvents revealed that the host itPMMA in the porous films could only form the original stereocomplex with 2/1 unit-molar stoichiometry (st-PMAA/it-PMMA) in acetonitrile/water or ethanol/water.