Fluorescence probe study of oil-in-water microemulsions. 1. Effect of pentanol and dodecane or toluene on some properties of sodium dodecyl sulfate micelles

Journal Article · Thu Mar 18 00:00:00 EST 1982 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100395a037· OSTI ID:5625952

Lianos, P; Lang, J; Strazielle, C; Zana, R

The analysis of the decay of the fluorescence of micelle-solubilized pyrene has been used to obtain for the first time the variation of the surfactant aggregation number n in micellar solutions of sodium dodecyl sulfate (SDS) upon addition of increasing amounts of 1-pentanol, and of oil (dodecane or toluene), thereby forming an oil-in-water (o/w) microemulsion. The polarity of the microenvironment of the micelle-solubilized pyrene, the intramicellar rate constant k/sub E/ for pyrene excimer formation, and the microviscosity eta sensed by dipyrenylpropane (DPyP) upon intramolecular excimer formation have been also investigated. The results indicate that the addition of pentanol to concentrated (> 0.2 M) SDS solutions results in an increase of n and a decrease of k/sub E/, eta, and microenvironment polarity. These effects have been associated with the transformation of the initially spherical SDS micelles into anisotropic (disk-shaped) large micelles upon dissolution of pentanol in the micelles. Upon addition of dodecane, eta goes through a minimum in the case of concentrated SDS + pentanol systems, but only shows a monotonous increase for less concentrated SDS + pentanol systems. For the former the variation of n has been attributed to a change of micelle shape from nonspherical to spherical, whereas for the latter the initially spherical micelles remain spherical upon dodecane solubilization. Similar variations of n are observed when dodecane is replaced by toluene in the case of dilute SDS + pentanol systems, whereas large differences are noted for concentrated SDS + pentanol systems. In the case where the results suggest the formation of oil-in-water microemulsion droplets, the calculations indicate that the oil core permeates part of the surfactant alkyl chains.

• Research Organization: CNRS, Strasbourg, France
• OSTI ID: 5625952
• Journal Information: J. Phys. Chem.; (United States), Vol. 86:6
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
MICROEMULSIONS
FLUORESCENCE
DODECANE
ENHANCED RECOVERY
MEDIUM TEMPERATURE
MICELLAR SYSTEMS
PENTANOLS
PYRENE
SURFACTANTS
TOLUENE
ALCOHOLS
ALKANES
AROMATICS
COLLOIDS
CONDENSED AROMATICS
DISPERSIONS
EMULSIONS
HYDROCARBONS
HYDROXY COMPOUNDS
LUMINESCENCE
ORGANIC COMPOUNDS
RECOVERY
020300* - Petroleum- Drilling & Production
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)