Pressure-induced phase transitions in micellar solutions

The crystallization behaviour of micellar solutions of tetradecyl-trimethylammonium-bromide has been investigated in a wide range of temperatures, pressures and electrolyte concentrations using the combination of small-angle neutron scattering and optical Raman scattering. The liquid to solid phase boundary is shifted to higher temperatures and lower pressures by the addition of NaBr. Time-dependent experiments yielded that the kinetics of the transition into the solid phase is rather sluggish and occurs on a time scale of hours. Moreover, intermediate metastable gel phases are observed along with a pronounced hysteresis of the phase transitions. (c) 2006 Elsevier B.V. All rights reserved.