Micelles alkarylsulfonates

Characterization of Inverted Micelles of Calcium Alkarylsulfonates by Some Pyrene Fluorescence Probes... 

Pyrene carboxaldehyde and a series of pyrene carboxylic acids were found useful as fluorescence probes in describing the constitution of inverted micelles of certain calcium alkarylsulfonates in hydrocarbon media. 1-Pyrene carboxaldehyde is a convenient probe for studying the particle sizes of micelles in the region of lOOA. A series of graded probes, pyrene carboxylic acids with varying alkyl chain length, have been used to determine internal fluidity and micro-polarity as a function of distance from the polar core of these Inverted micelles. Pyrene exclmer to monomer fluorescence intensity ratio and fluorescene lifetime provided the means of measurement of internal fluidity and micropolarity, respectively. 

The present study demonstrates the utility of the above probe in describing the constitution of aggregates of certain alkarylsulfonates in hydrocarbon media. It also demonstrates the use of the probe technique in measuring the micropolarity of these same aggregates as a function of distance from the polar core. The micro-viscosity of inverted or normal micelles in the past has been estimated only as an average value of either the polar or non-polar regions (6). 

Pyrene Carboxaldehyde in Calcium Alkarylsulfonates. Our work shows that 1-pyrene carboxaldehyde as a fluorescent probe for the sulfonate systems behaves very much the same as rhodamine B (1 ) and anillnonaphthalene sulfonate (2), whose fluorescence intensities in hydrocarbon media are enhanced in the presence of inverted micelles. However, the intensity Increase observed with AOT was considerably less than that observed with the sulfonates. It is speculated that... 

Lateral Mobility in Alkarylsulfonate Micelles. In order to make a valid comparison of fluidity between sulfonates A and B, the micellar sizes should be comparable. This condition is required so that equal population of pyrene moieties between the two sulfonate systems can be assumed. Alternatively, the requirements might be met if they have equal aggregation numbers. If the above-mentioned (See Section A under "Results") assumptions regarding polar core composition are reasonable, the condition for equal probe population between the two sulfonate micelles can still be reasonably approximated. 

Variation of lateral mobility (fluidity) and polarity gradient have been reasonably established in certain calcium alkarylsulfonate micelles using 1-pyrene carboxylic acid probes with varying alkyl chain lengths. The existence of a polarity gradient in an inverted micelle may be responsible for the creation of an oxygen concentration gradient. 

Jao, T. C. Kreuz, K. L. Characterization of inverted micelles of calcium alkarylsulfonates by some pyrene fluorescence probes. ACS Symp. Set 1986, 311, 90-99. 

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