小角X射线散射法测定溶胶平均界面厚度

DETERMINATION OF THE AVERAGE THICKNESS OF INTERFACE LAYER WRAPPED ABOUT SiO_2 SOLS BY SAXS

溶胶界面层厚度通常是用Porod法对高角区负偏离的Porod曲线进行拟合求算 ,但本文研究表明还可通过分别测定Porod负偏离校正前后体系粒子的平均半径之差而获得平均界面厚度 .

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 new method that includes the following steps:(1) determining the average radius 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 negative deviation from Pored's law;(3) the difference DeltaR between R-1 and R-2, i.e. DeltaR = R-1 - R-2 , is just the average thickness of the interface layer wrapped about sols. By using the above method,the average thickness of the interface layer wrapped about SiO2 sols prepared under different conditions were determined.