title: Preparation and dilute solution properties of model gemini nonionic surfactants.
abstract: Dimeric poly(ethylene oxide) surfactants (or nonionic gemini surfactants) with the structure (Cn-2H2n-3CHCH2O(CH2CH2O)mH)2(CH2)6 (or GemnEm), where n is the alkyl length and m is the average number of ethylene oxides per head group, were synthesized. Surfactants were synthesized with alkyl chain lengths n = 12, 14, and 20 and m = 5, 10, 15, 20, and 30. Water solubilities and cloud temperatures at 1 wt% were determined by measuring turbidity as a function of temperature. Cloud temperatures increase with m and decrease with n, as observed for conventional surfactants. For large m the cloud temperatures were all above 100 degrees C. Surfactants with small m (i.e., n = 12, 14, m = 5 and n = 20, m = 10) were insoluble at room temperature, forming two-phase mixtures. Critical micelle concentrations (CMCs) were measured using a pyrene fluorescence method and are all in the range of 10(-7) to 10(-6) M, with the lowest values from the surfactants with large n and small m. CMCs of mixtures with both anionic and nonionic conventional (monomeric) surfactants were well described by an ideal mixing model.
authors.affiliation: School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: FitzGerald
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Carr
authors.forename: Tim W
authors.initials: TW
authors.lastname: Davey
authors.forename: Algirdas K
authors.initials: AK
authors.lastname: Serelis
authors.forename: Chris H
authors.initials: CH
authors.lastname: Such
authors.forename: Gregory G
authors.initials: GG
authors.lastname: Warr