COLL 241 |
| Gina A. Sorci and Thomas D. Walker. Department of Physics, Millsaps College, 1701 North State St., Jackson, MS 39210 |
| A phenomenon observed near the critical micelle concentration (CMC) of surfactants is explored using static light scattering. A special mixing technique has been utilized here which has been applied previously to other systems with great success. It incorporates a gradient mixer and pump linked with static light scattering and refractometer detectors which is used to determine the concentration. Using this technique we are able to observe phenomena as they occur and in great detail due to the ability to control the concentration range. What is observed in the light scattering is a large increase followed by a decrease (peak) in light scattering near the CMC. This work looked at three different surfactants in order to obtain a better understanding of what the peak is caused by; two ionic surfactants hexadecyltrimethylammonium bromide (CTABr) and sodium dodecyl sulfate (SDS), and a non ionic surfactant Triton-X 100. The peak was seen for both ionic surfactants but it was not seen for the non ionic surfactant suggesting a purely electrostatic effect may be taking place. These effects are observed under different conditions such as varying ionic strengths and different concentration paths. These peaks appear to be real and can be described using fluctuation theory for the light scattering of molecules.
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Posters: Fundamental Research in Surface and Colloid Chemistry
6:00 PM-8:00 PM, Monday, March 29, 2004 Disneyland -- North Exhibit Hall, Poster
Division of Colloid and Surface Chemistry |