An investigation of the structure of mesomorphic phases by electron microscopy

Pure surface-active compounds have been prepared which exist in the mesomorphic state in a high vacuum. An examination of surface replicas of the anhydrous neat phase given by sodium 2-ethylhexyl sulphate and of the anhydrous middle phases given by several homologues of sodium di-2-ethylhexyl sulphosuccinate has shown that both neat and middle mesomorphic phases possess stepped growth patterns. In both cases the step-height measurements agree with the interlayer spacings determined by low-angle X -ray diffraction and are consistent with layers having a thickness approximately equal to the length of two surface-active molecules. Topographical differences between neat and middle phase have been related to their different structures.