Solvent quality affects chain conformational order at the polymer surface revealed by sum frequency generation vibrational spectroscopy

The surface sum frequency generation (SFG) vibrational spectroscopic spectra of PMA and PMMA films prepared from solvents with different qualities were found different. This suggests that the surface molecular structures of PMA and PMMA films were affected by the solvent quality. A simple phenomenological model was used to describe the chain conformational order at the polymer surface by correlating the SFG resonant signals of the side chromophoric groups to the introduced chain arc included angle. This model is believed to be applicable for polymers with short and rigid side chromophores active for the SFG spectroscopy.