FREEZE-FRACTURE ELECTRON-MICROSCOPY OF THERMOTROPIC CUBIC AND COLUMNAR MESOPHASES

Freeze-fracture electron microscopy has been applied to study thermotr opic columnar and cubic phases of a polycatenar liquid crystal of silv er(I). The columnar phases displayed hexagonal type II characteristic fracture planes. The cubic phases showed a fracture behaviour highly c haracteristic of the Ia (3) over bar d type II (Q(230)II) cubic space group, namely the high frequency of well ordered domains perpendicular to the [2 1 1] crystallographic axis and, much less frequently, the f ragmented aspect of domains perpendicular to the [1 1 0] crystallograp hic axis. For both types of domain, the observed 2-D lattice parameter s were in excellent agreement with the ideal values expected for the Q (230) cubic space group.