Mesoporous silica powders and films—Pore size characterization by krypton adsorption

An experimental correlation was established between pore size derived from N2 adsorption, DN2DN2, and capillary condensation/evaporation pressure, (P/P0)t,Kr, obtained from Kr adsorption/desorption isotherms on powdery siliceous MCM-41, MCM-48 and SBA-15 samples, and was analyzed by the DBdB theory. The correlation was then used to estimate the pore size distribution from the Kr adsorption isotherm of mesoporous silica layers on Si(1 0 0) wafer prepared using P123 and Brij®56 surfactants. It was found by TEM analysis that the pore shape in the thin films was distorted from circular to ellipsoidal, leading to different pore sizes estimated from the adsorption and desorption branches of the Kr isotherm.