Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [15] hydration structures of a PMEA film contacting with water

Hydration structures of a biocompatible polymer, poly(2-methoxyethyl acrylate) (PMEA), were investigated by in-situ ATR-IR spectroscopy. Time-resolved in-situ ATR-IR spectra of water sorption process into a PMEA film from dried condition to saturated hydration were monitored. Difference spectra, i.e., subtraction spectra at each time step A(t_n) - A(t _n-1), revealed that the band around 3600 cm^-1 assigned to non-freezing water initially arises, followed by that around 3400 cm ^-1 of freezing bound water, and finally the band around 3200 cm ^-1 corresponds to freezing water increases. Hydration structures of each water in PMEA will be discussed in detail.