Aging process of some pyrogenic silica samples exposed to controlled relative humidities: Part II: Evolution of their surface properties studied using inverse gas chromatography

Abstract In the present study, we have examined the influence of the aging process under controlled relative humidity on the surface properties of 3 silicas samples of increasing specific surface area. Both comparison of the specific surface areas, determined using either nitrogen (BET) or cetyltrimethylamonium bromide (CTAB), and the surface nanoroughness indexes, determined by size exclusion inverse gas chromatography, indicates that the ageing process has no significant influence on the surface morphology at the molecular level. On the contrary, IGC at finite concentration using isopropanol as probe evidences clearly an increase of the surface heterogeneity induced by the formation of new silanol groups into the preexisting hydrophilic domains by opening of siloxane bridges by water.