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Title: Quaternary water in oil microemulsions. 1. Effect of alcohol chain length and concentration on droplet size and exchange of material between droplets

Water solubility, electrical conductivity, and time-resolved fluorescence quenching measurements have been performed in water/chlorobenzene/cationic surfactants/1-alcohol water-in-oil (w/o) microemulsions in order to investigate the effect of alcohol chain length and concentration on various properties of these systems: surfactant aggregation number, N, per aggregate; radius, R{sub w}, of the droplet water core; intensity of attractive interdroplet interactions; onset of percolation of electrical conductivity; and rate constant, k{sub e}, for the exchange of material between droplets through collisions with temporary merging. The variations of these properties with the molar concentration ratio {omega} = (water)/(surfactant) for alcohols of increasing chain length are strikingly similar to those found when investigating the effect of surfactant chain length. In particular, N and R{sub w} and the intensity of attractive interactions decrease when the alcohol chain length increases as predicted by current theory of the stability of w/o microemulsions. For a series of microemulsions based on alkyltrimethylammonium bromide surfactants, the water solubility results indicate that the stability of the microemulsions containing short chain alcohols (propanol, butanol) is determined by the attractive interdroplet interactions. The results give support to the mechanism postulated for electrical conductivity above the percolation threshold, namely, motion of counterions through transient water tubes formed inmore » the droplet clusters present in the systems. Finally, it is shown that simple electrical conductivity and water solubility measurements can yield of quantitative information about the investigated microemulsions.« less
Authors:
; ;  [1]
  1. (Inst. Charles Sadron (France))
Publication Date:
OSTI Identifier:
7017457
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry; (United States); Journal Volume: 95:23
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 02 PETROLEUM; CHLORINATED AROMATIC HYDROCARBONS; FLUORESCENCE SPECTROSCOPY; PHYSICAL PROPERTIES; OILS; SURFACTANTS; WATER; CATIONS; DROPLETS; ELECTRIC CONDUCTIVITY; EXPERIMENTAL DATA; MASS TRANSFER; MICROEMULSIONS; PARTICLE SIZE; QUANTITY RATIO; QUENCHING; SOLUBILITY; TIME RESOLUTION; AROMATICS; CHARGED PARTICLES; COLLOIDS; DATA; DISPERSIONS; ELECTRICAL PROPERTIES; EMISSION SPECTROSCOPY; EMULSIONS; HALOGENATED AROMATIC HYDROCARBONS; HYDROGEN COMPOUNDS; INFORMATION; IONS; NUMERICAL DATA; ORGANIC CHLORINE COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; OTHER ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; PARTICLES; RESOLUTION; SIZE; SPECTROSCOPY; TIMING PROPERTIES 400201* -- Chemical & Physicochemical Properties; 020300 -- Petroleum-- Drilling & Production