The lamellar and sponge phases of dilute surfactant systems: Structures and defects at equilibrium and under shear

We report on the physical properties of swollen solutions of the amphiphili c molecules of cetylpyridinium chloride and hexanol in brine. A remarkable characteristic of this system is the existence of a crossover between dilut e and less dilute solutions, in the lamellar phase and the sponge phase, wi th some interesting consequences for the theory of membranes.