title: Morphology transitions in nonionic surfactant adsorbed layers near their cloud points.
abstract: The structure of adsorbed layers of several polyoxyethylene alkyl ether (C(n)E(m)) nonionic surfactants on silica and graphite surfaces has been imaged using atomic force microscopy as a function of temperature up to their cloud points. For all surfactants with a cloud point within the experimentally accessible range, the adsorbed layer morphology on silica evolved from globules at low temperatures first into rods and then a mesh with increasing temperature. This mesh structure was retained even when the solutions were heated above their cloud points into the two-phase coexistence region. Only C(12)E(3) was observed to form a laterally unstructured bilayer. On graphite, all surfactants formed straight, parallel hemicylinders at all temperatures examined.
authors.affiliation: School of Chemistry, The University of Sydney, NSW, Australia.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Blom
authors.forename: Gregory G
authors.initials: GG
authors.lastname: Warr
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Wanless
mesh_terms: D000327:Adsorption; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature
chemical_list: D012996:Solutions; D013501:Surface-Active Agents