title: Stability of a Nanometric Zirconia Colloidal Dispersion under Compression: Effect of Surface Complexation by Acetylacetone
abstract: The stability of a colloidal dispersion of nanometric zirconia particles has been studied during a compression process. Using the osmotic stress method, cycles of compression and reswelling were applied to the dispersion to test the reversibility of the process. Original dispersions are stable in a very limited pH range (0.5-2). At pH 3, the bare particles aggregate irreversibly under compression as checked by osmotic pressure and light and X-ray scattering measurements. To improve the stability, small organic complexing molecules (acetylacetone) were added to the original dispersion. The adsorbed monolayer on the particle surfaces acts as a steric barrier and prevents the two colloids from contacting. As a consequence, the dispersion becomes more compressible and the compression cycle is totally reversible. The experimental data are quantitatively reproduced with a classical theory of statistical mechanics of liquids based on a DLVO-like colloid-colloid potential.
authors.affiliation: Service de Chimie Moleculaire, CEA/SACLAY, Gif sur Yvette Cedex, 91191, France
authors.initials: V
authors.lastname: Peyre
authors.initials: O
authors.lastname: Spalla
authors.initials: L
authors.lastname: Belloni
authors.initials: M
authors.lastname: Nabavi