It has been recently shown that the system potassium laurate– decanol–water presents three nematic phases, two uniaxial and one biaxial. We are currently investigating the structure of these phases by scattering methods. The study reported here describes the first experiment, neutron scattering with contrast variation, which demonstrates that the aggregates in one uniaxial phase in the vicinity of the transition to the biaxial phase are statistically biaxial. This observation provides a new insight into the uniaxial-biaxial phase transition.

• Received 8 July 1985

DOI:https://doi.org/10.1103/PhysRevB.33.3534