Abstract: The phase transition of 400% sodium dodecyl sulfate (SDS)/water system has been studied by employing pyrene as a fluorescent probe in the temperature range of -20 ℃—+30 ℃. The binary system mainly undergoes coagel-liquid crystal phase transition at about 20 ℃. Free water layer melts at 0 ℃, below and above that different coagel phases were found. Anoval coagel phase was brought forth after annealing at -17 ℃ for 12 hours. All these phases have been fairly characterized by I_E/I_M. Structurual aspects of these phases are idscussed concerning with the fluorescence information.

Key words: Sodium dodecyl sulfate/water, Pyrene, Fluorescence probe, Phase transition