Phase Behavior and Phase Structure of a Cationic Fluorosurfactant in Water
2000 (English)In: Langmuir, Vol. 16, no 3, 1042-9 p.Article in journal (Refereed) Published
The phase behavior of the cationic fluorocarbon surfactant 1,1,2,2-tetrahydroperfluorodecylpyridinium chloride in water has been studied using small-angle X-ray and 2H NMR spectroscopy as the main techniques. The following phase sequence was found: micellar (L1), hexagonal (HI), centered rectangular (R; spacegroup c2mm) and centered trigonal (T, spacegroup Rm) with increasing surfactant concentration. At higher concentrations evidence for random mesh phase and a lamellar phase was found, at high temperatures a bicontinuous cubic phase was found. Compared to a cationic hydrocarbon surfactant of similar hydrophobicity, the occurrence of the intermediate phases is more extensive in the phase diagram, and the fluorocarbon surfactant prefers to form intermediate phases instead of a cubic phase. The surface curvature of the aggregates changes from highly curved cylindrical structures of the hexagonal phase to the planar bilayer structure of the lamellar phase over a sequence of geometries that allow the average of the mean curvature to change gradually as water content is decreased.
Place, publisher, year, edition, pages
2000. Vol. 16, no 3, 1042-9 p.
IdentifiersURN: urn:nbn:se:umu:diva-8634DOI: doi:10.1021/la9909603OAI: oai:DiVA.org:umu-8634DiVA: diva2:148305