Freeze-fracture electron microscopy of thermotropic cubic and columnar mesophases

Freeze-fracture electron microscopy has been applied to study thermotropic columnar and cubic phases of a polycatenar liquid crystal of silver(I). The columnar phases displayed hexagonal type II characteristic fracture planes. The cubic phases showed a fracture behaviour highly characteristic of the Ia 3 d type II (Q230II) cubic space group, namely the high frequency of well ordered domains perpendicular to the \[2 1 1] crystallographic axis and, much less frequently, the fragmented aspect of domains perpendicular to the \[1 1 0] crystallographic axis. For both types of domain, the observed 2-D lattice parameters were in excellent agreement with the ideal values expected for the Q230 cubic space group.