Analysis of surface structure and hydrogen/deuterium exchange of colloidal silica suspension by contrast-variation small-angle neutron scattering.
The microscopic surface structure and hydrogen/deuterium exchange effect were investigated by contrast-variation small-angle neutron scattering (CV-SANS) for three different-sized amorphous colloidal silica aqueous suspensions. The results show that the fraction of hydrogen/deuterium exchange per nanoparticle, phiH/D, strongly depends on the size of silica nanoparticles. This finding supports that the hydrogen/deuterium exchange occurs exclusively within a finite surface layer of silica nanoparticles, while the inner component remained unchanged. Detailed analyses of the scattering intensity functions led to the estimation of (1) phiH/D and (2) the thickness of the surface layer as functions of the particle radius. The surface layer thickness was found to increase from 18 to 35 A with decreasing the particle radius from 165 to 71.2 A. The surface area per unit weight of silica estimated with the CV-SANS results are comparable to those reported in the literature.
Suzuki
Takuya
T
Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
Endo
Hitoshi
H
Shibayama
Mitsuhiro
M
D003102:Colloids / Q000737:chemistry; D041961:Deuterium Exchange Measurement; D008956:Models, Chemical; D009502:Neutrons; D053838:Scattering, Small Angle; D012822:Silicon Dioxide / Q000032:analysis* / Q000737:chemistry*; D013499:Surface Properties
D003102:Colloids; D012822:Silicon Dioxide