Fourier-transform infrared spectroscopy studies of the interaction of functionalized siloxane polymers with porous silica

Adsorption behavior of the siloxane polymer, cyanopropyl-methyl-phenyl-meth yl-siloxane, in contact with a mesoporous silica has been investigated by F ourier-transform infrared spectroscopy (FT-IR) using a series of physically modified materials with different coating levels up to 20 w/w%. The nitril e stretch bands, which are observed in the 2150-2350 cm(-1) range, exhibite d complex profiles due to a variety of interactions of the cyano groups wit hin the polymer and with the surface silanols. These complex bands have bee n resolved into multiple components using a curve-fitting procedure, Three major spectral components have been found and assigned to the nitrile stret ch in the bulk polymer, interfacial polymer, and polymer attached to surfac e silanols via hydrogen bonding. The latter spectral component is dominatin g for the samples with low coating levels, Its relative contribution decrea sed with the increasing amount of the polymer on the silica surface due to increasing contribution of the pure-polymer spectral component. (C) 2000 Ac ademic Press.