Influence of polydispersity on adsorption of nanoparticles

The adsorption of polydisperse, interacting nanoparticles is studied experi mentally and discussed in terms of the random sequential adsorption model. Two kinds of polystyrene particles with different size variation (41 +/- 6 and 107 +/- 5 nm) were used in adsorption experiments at or close to satura tion. The dried monolayer particle films were analyzed with scanning electr on microscopy. Selective adsorption of smaller particles resulted in altere d size distributions on the surface compared to that in solution. Varying t he ionic strength was seen to influence the effective polydispersity of the particles. With increasing salt concentration there was a relative increas e in the adsorption of smaller particles, resulting in a large shift toward smaller particle sizes in the size distribution on the surface. Polydisper sity gave a slight increase in coverage at high salt concentrations and a d ecrease in the ordering of the particles on the surface. (C) 2001 Academic Press.