화학공학소재연구정보센터
Langmuir, Vol.16, No.5, 2141-2144, 2000
Fluctuating clouding behavior in mixed micellar solutions
The clouding behavior of mixed surfactant (Triton X-114/sodium dodecyl sulfate) systems, as manifested by solution turbidity, was studied over a range of concentrations and temperatures. The results were correlated with particle size data obtained from dynamic light scattering measurements. Fluctuating behavior, involving clouding at relatively low temperatures, (partial) clarification upon further heating ("declouding"), and definitive clouding at still higher temperatures, was observed. The temperature ranges and solution compositions producing declouding were found to coincide roughly with a previously reported preclouding phenomenon. In this, clouding occurs in two stages, starting with a relatively stable colloidal suspension displaying a Tyndall effect, and proceeding to full clouding at higher temperatures. Both pre-and declouding were found to be promoted by the presence of anionic sodium dodecyl sulfate in the micellar Triton X-114 solution. A modified charge accumulation mechanism is proposed to account for the fluctuations.