Fine structure in cholesteric fingerprint texture observed by scanning electron microscopy

The fine structure in some cholesteric fingerprint textures of cyanoethyl c hitosan (CNCS)/acrylic acid solution and photo-solidified CNCS/polyacrylic acid composite film was studied using scanning electron microscopy (SEM), s mall angle light scattering (SALS) and polarizing optical microscopy (POM). Permanganic etching was developed to reveal the cholesteric liquid crystal line textures in the composite films. A schematic model was presented to ex plain this kind of fine structure. The directors within each cholesteric mo lecular layer did not orient in nematic-like order, but varied their orient ation by an ill-defined period.