Fourier Transform Infrared Imaging of Stereoregular Poly(Methyl Methacrylate) Dissolution

Fourier transform infrared (FT-IR) imaging was used to study dissolution of stereoregular poly(methyl methacrylate) (PMMA) films in toluene, benzene, chloroform, acetic acid, and 2-ethoxyethanol. Images of the polymer-solvent interface showed that syndiotactic (sPMMA), atactic (aPMMA), and isotactic (iPMMA) samples dissolved in acetic acid and chloroform; only iPMMA dissolved in benzene, toluene, and 2-ethoxyethanol. Concentration profiles allowed quantitative comparison of each polymer-solvent system. In the cases of chloroform and acetic acid, the rate of polymer dissolution increased with increasing isotacticity. Dissolution of PMMA in chloroform was observed to coincide with development of strong polymer-solvent interactions. The results of systems containing toluene, benzene, and 2-ethoxyethanol reflect kinetic effects on dissolution, including solvent size and stiffness of the polymer backbone.