Polymorphism in a Lamellar Liquid-Crystal Bilayer System

The lamellar liquid-crystal phase, $L_{\alpha }$, of the potassium-palmitate-water system is shown to be actually polymorphic. Using deuterium magnetic resonance as well as birefringence observations, two sharp phase transitions are observed in the simple neat soap bilayers. Optical conoscopy shows the high-temperature phase to be uniaxial and the other two to be biaxial. Deuteron magnetic resonance shows that each phase transition is accompanied by a change in orientational order.