Determination of the average thickness of interface layer wrapped about SiO2 sols by saxs

The average thickness of the interface layer wrapped about sols usually is determined by fitting the Pored curve that shows a negative deviation from Pored's law. In this paper we show that it could also be determined by a ne w method that includes the following steps:(1) determining the average radi us R-1 of the sol particles including interface layer from the small angle X-ray scattering data in which shows negative deviation from Pored's law;(2 ) determining the average radius R-2 of the sol particles not including the interface layer from the scattering data in which has been corrected the n egative deviation from Pored's law;(3) the difference DeltaR between R-1 an d R-2, i.e. DeltaR = R-1 - R-2 , is just the average thickness of the inter face layer wrapped about sols. By using the above method,the average thickn ess of the interface layer wrapped about SiO2 sols prepared under different conditions were determined.