title: Effect of ultrasonication and dispersion stability on the cluster size of alumina nanoscale particles in aqueous solutions.
abstract: This study deals with the deagglomeration of nanoparticles in low concentration suspensions in water, protic polar solvent for polymers such as poly(vinyl alcohol) (PVA). The influence of the main parameters of ultrasonication such as time, power and irradiation modes (continuous, pulsed) on the cluster size of aluminium oxide nanoparticles 1 mg/ml in aqueous solutions was investigated. Power-law dependence of size reduction on ultrasonic time was observed. The study indicated an optimum power input, i.e. at higher vibration amplitude the break up of nanoparticle clusters was no better and there was a risk of reagglomeration occurring during a long ultrasonication. Under optimal conditions, continuous and pulsed irradiations showed almost the same efficiency of deagglomeration over a given time. This result provides alternative operating conditions for attaining the smallest size of the alumina aggregates in suspension. The influence of stabilization on the cluster size was also studied. Alumina nanoparticles were stabilized by electrostatic forces against reagglomeration without the need for dispersants, and the enhancement of dispersion stability using electrostatic, steric effects had no significant effect on the aggregate size. On the contrary, the adsorption of high molecular weight polyelectrolytes onto the particle surface could lead to reagglomeration due to material bridges between particle surfaces and even flocculation.
authors.affiliation: Institut Jean Lamour-UMR CNRS 7198, Faculté des Sciences et Techniques, Campus Victor Grignard-BP 70239, 54506 Vandoeuvre-les-Nancy Cedex, France.
authors.forename: Van Son
authors.initials: VS
authors.lastname: Nguyen
authors.forename: Didier
authors.initials: D
authors.lastname: Rouxel
authors.forename: Rachid
authors.initials: R
authors.lastname: Hadji
authors.forename: Brice
authors.initials: B
authors.lastname: Vincent
authors.forename: Yves
authors.initials: Y
authors.lastname: Fort
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D012996:Solutions; D013535:Suspensions / Q000737:chemistry; D014465:Ultrasonics; D014867:Water / Q000737:chemistry
chemical_list: D012996:Solutions; D013535:Suspensions; D014867:Water; D000537:Aluminum Oxide