Accession Number : ADA133801

Title :   Diffusion Measurements in Microemulsions.

Descriptive Note : Final rept. Sep 82-Dec 83,

Corporate Author : ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERDEEN PROVING GROUND MD CHEMICAL SYSTEMS LAB

Personal Author(s) : MacKay,R A ; Dixit,N S ; Agarwal,R ; Seiders,Reginald P

PDF Url : ADA133801

Report Date : Jun 1983

Pagination or Media Count : 17

Abstract : Diffusion coefficient measurements in both aqueous micelles and microemulsions have been carried out using the techniques of polarography and quasielastic light scattering (QLS). The former method involves the determination of the diffusion coefficient of an electroactive oil soluble probe at a polarizable microelectrode. For high water content microemulsions, both methods yield the same diffusion coefficients which can be identified as the self diffusion coefficient. For cetyltrimethylammonium bromide (CTAB) micelles, both methods yield the same result at the salt (NaBr) concentration at which the QLS measurements are independent of CTAB concentration. In more concentrated microemulsions, QLS data gave diffusion coefficients, in agreement with polarography only for a sodium cetyl sulfate (SCS) system at 65-75 wt % water. For the SCS microemulsions at 60% water, and CTAB microemulsion at 60-75% water, the QLS data yielded rapid, nonexponential decays. However, consistent polarographic diffusion coefficients could still be obtained. By using probes of varying chain length (oil solubility), it has been demonstrated that these CTAB and SCS microemulsions containing butanol and pentanol cosurfactants respectively, are not cosolubilized systems but do contain distinct hydrophilic and hydrophobic regions. (Author)

Descriptors :   *Emulsions, *Diffusion coefficient, Diffusion, Measurement, Colloids, Polarographic analysis, Elastic scattering, Light scattering, Ammonium compounds, Sulfates, Decay, Oils, Solubility, Hydrophilia, Hydrophobic properties, Surface active substances, Pentanols, Butanols, Probes, Bromides, Sodium compounds

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE