The effect of pH on the adhesion of silica and polystyrene latex nanoparticles, presenting hydroxyl and carboxylic acid surface chemistries respectively, to self-assembled monolayers (SAMs) has been investigated. The SAMs studied were 1-dodecanethiol, 11-mercaptoundecanoic acid and an original pyridine-terminated SAM. Adhesion of nanoparticles to the SAMs was found to decrease with increasing pH due to increased repulsive forces between surfaces, as a result of the deprotonation of surface moieties on the nanoparticles. A range of surface morphologies for the adsorbed nanoparticles was observed for the systems studied. (c) 2007 Elsevier B.V. All rights reserved.