Self-assembly structures of nonionic surfactants at graphite-solution inter-faces. 2. Effect of polydispersity and alkyl chain branching

The structure of the adsorbed film of poly(oxyethylene) nonionic surfactants on graphite and in equilibrium with aqueous solutions is examined by atomic force microscopy. In particular attention is paid to the effects of (i) polydispersity in the ethoxylation and (ii) changes in alkyl chain structure on the morphology of the adsorbed surfactant film. Polydispersity is shown to have little influence on adsorbed film structure, but modifications of the alkyl chain structure which compromise the templating ability of the graphite can completely disrupt lateral structure. (C) 2000 Elsevier Science B.V. All rights reserved.