Monolayers of a cellulosic polymer bearing cinnamate groups were characterized at the air–water interface by combining isotherm measurements, Brewster angle microscopy, and infrared–visible sum-frequency generation (SFG) spectroscopy. This spectroscopic technique was used to detect the photochemical behavior of the cinnamate groups upon UV photoirradiation of the monolayers. From the disappearance of the C═C mode and the absence of a change in the C═O mode, it could be concluded that isomerization is the dominant photoreaction for a monolayer of this polymer. This conclusion was corroborated by a comparison of the spectra of the monolayer after irradiation with spectra measured for monolayers spread from preirradiated solutions, for which it is known that isomerization is the main process.

J. Phys. Chem. B

Backus, E.H.G, Abrakhi, S, Péralta, S, Fichet, O, & Cantin, S. (2012). Sum-frequency generation spectroscopy of cinnamate modified cellulosic polymer at the air-water interface. J. Phys. Chem. B, 116. doi:10.1021/jp301844b