MACROMOLECULAR CHOLESTERIC ORDER OBSERVED BY ELECTRON-MICROSCOPY

The macromolecular cholesteric structure in the ethyl-cyanoethyl cellu lose [(E-CE)C]/acrylic acid [AA] cholesteric liquid crystalline soluti ons is studied by direct ly observing the morphology and structure of the ethyl-cyanoethyl cellulose [(ECE)C]/polyacrylic acid [PAA] using e lectron microscopy. A periodical lamellar structure is observed in ult rathin slices of the composites with cholesteric order by both transmi ssion electron microscopy (TEM) and low-voltage scanning electron micr oscopy (LVSEM). It is suggested that the periodical lamellar structure is induced by the twist of the molecular orientation in the cholester ic phase and reflects the structural features of the macromolecular ch olesteric phase. The macromolecular cholesteric phase exhibits the twi sted ring morphology in the initial stage of the formation of the liqu id crystalline phase. The swelling of the ultrathin slices with choles teric order in water is heterogeneous, which suggests the tight packin g of the (E-CE)C chains in the direction of the helix axis in the macr omolecular cholesteric phase. (C) 1998 John Wiley & Sons, Inc.