Lyotropic mesophase of imogolite, 3 observation of liquid crystal structure by scanning electron and noval polarized optical microscopy

Abstract

Abstract The mesophase (lyotropic liquid crystal) of the inorganic rod‐like polymer, imogolite, displays a typical fingerprint texture under a polarized optical microscope (POM), although the mesophase reveals no circular dichroism. The scanning electron microscope revealed a honeycomb structure of thin sheets having pleats in the freeze‐dried sample prepared from the mesophase solution, and POM shows also a fingerprint texture from the same sample. A novel polarized optical microscopic observation procedure was introduced to eliminate the contrast variation and extinction due to the zero amplitude effect which depends on the orientational variation of anisotropic bodies with respect to a polarizer direction under the crossed Nicols. Various textures of lyotropic imogolite liquid crystals were observed with the procedure, and the results were accounted for by a honey‐comb structure of curled thin sheats having pleats. The honey‐comb model is consistent with the observation by scanning electron microscopy on the freeze‐dried sample.