Electron Diffraction Study of Freely Suspended Liquid Crystal Films

We have carried out the first electron diffraction study of thin freely suspended liquid crystal films. To maintain stable films, they were contained in a temperature controlled atmosphere of several Torr using a differentially pumped hot-stage. The sample area probed could be as small as 5 microns making it possible to observe single domains even in thin hexatic films. Specifically, results indicative of single-domain diffraction have been obtained in films 2 to 4 molecular layers thick for the crystal B phase of N-(4'- n- butyloxybenzylidene)-4-n-octylaniline (40.8) and the hexatic I phase of S-N-(4-(3,7-dimethyloctanoyloxy) -2- hydoxybenzylidene)- 4-n -nonylaniline. Diffraction results on the latter compound will be correlated with optical observations on the films using polarized reflected-light microscopy.