Dynamical study of the water penetration process into a cellulose acetate film studied by coherent anti-Stokes Raman scattering (CARS) microspectroscopy

Abstract

The penetration process of water into a cellulose acetate film was traced in real time by coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The CO stretch mode was red-shifted due to hydrogen-bond formation. We also found that two Raman bands at 1605cm−1 and 1665cm−1 emerged only in the early stage of the water penetration process. Based on the combined analysis of the experimental and computational studies, these bands at 1605cm−1 and 1665cm−1 were assigned as the OH bend mode due to hydrogen-bonded penetrated water and hydrogen-bonded OH groups in pyranose rings, respectively.