CHARACTERIZATION OF SILYLATED SILICAS BY INVERSE GAS-CHROMATOGRAPHY -MODELIZATION OF THE POLY(DIMETHYLSILOXANE) MONOMER UNIT SURFACE INTERACTIONS USING POLY(DIMETHYLSILOXANE) OLIGOMERS AS PROBES/

Inverse gas chromatography (IGC) at infinite dilution was used to char acterize the fumed silica surface. The silica was modified by chemical treatment with either dimethyldichlorosilane or trimethylchlorosilane . To observe the silica and poly(dimethylsiloxane) (PDMS) interactions , we used apolar (alkanes) and polar probes (chloroform, benzene, tetr ahydrofuran, etc.), but also model molecules of PDMS such as linear an d cyclic oligomers of PDMS with two to five monomer units. It is shown that PDMS oligomers are very appropriate to discriminate the silylate d silicas. (C) 1996 Academic Press, Inc.