Observation of the parabolic focal conic structure and a disclination/dislocation relationship in a dilute lyotropic phase

Observations of the parabolic focal conic (PFC) structure are reported in a dilute lamellar lyotropic liquid crystalline phase. Only recently did Rosenblatt et al. [1] present the theory of this structure and its observation in a thermotropic smectic A phase. The PFC structure forms spontaneously in the lyotropic phase, and various structural details exhibit unusual resolution from polarizing microscopy. In particular two disclinations of opposite sign are clearly observed at the node of an edge dislocation and are conveniently explained in terms of the tetragonal lattice space group.