Electrophoretic microrheology in a dilute lamellar phase of a nonionic surfactant.

We measured the complex electrophoretic mobility mu(*)(omega) of nanometer-sized particles dispersed in a lyotropic lamellar phase, and observed two relaxation processes corresponding to the two characteristic lengths of lamellar structure. Faster relaxation is caused by the distortion field of lamellar phase induced by the colloidal particles, and slower relaxation is presumably due to the defects in lamellar structure. Since the dynamic transport property is strongly influenced by the microscopic circumstances as shown in this paper, this method is referred to as electrophoretic microrheology.