LIGHT-SCATTERING INVESTIGATION OF PHASE-SEPARATION IN A MICELLE SYSTEM

A real-time, two-dimensional light scattering study is reported of the evolution of structure in a two-component non-ionic micelle system du ring phase separation via spinodal decomposition. The principal findin g is that domain growth proceeds much slower than the cube root of tim e prediction for simple binary fluids. In fact, the growth kinetics ca n be empirically described as a stretched exponential approach to a pi nned domain size. Although the kinetics are not yet understood, this a nomalous behavior may be due to the ability of the spherical micelles to reorganize into more complex structures. The domain structure also shows some anomalies. Although at short times the expected structure f actor for a critical quench is observed, at long times the structure f actor crosses over to the off-critical form. However, in all cases the average scattered intensity is proportional to the cube of the domain size. These findings are discussed by comparison with standard theori es of and experimental work on binary fluids.