SMALL-ANGLE NEUTRON-SCATTERING STUDY OF VANADIUM PENTOXIDE GELS SWELLING

Concentration dependent changes in the structure of Y2O5, nH2O gels has been followed by small angle neutron scattering (SANS) in the composition range 10 ≤ n ≤ 800. Up to n = 50, a one-dimensional mode, where the interlamellar distance increases up to a value comparable with the width of the V2O5-ribbons, is first observed. Then a two-dimensional swelling corresponding to a viscous liquid state is obtained between 150 and 800 H2O V2O5. The mean interparticle distance increases up to about 700 Å. A transition region appears between two swelling regimes corresponding to the thixotropic state of the gel. © 1991.