PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS*

 Ethyl-cyanoethyl cellulose (E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution withvivid colors when the (E-CE)C concentration is 42 wt%～52 wt%. (E-CE)C/polyacrylic acid (PAA) composites withcholesteric structure were prepared by polymerzing AA in (E-CE)C/AA liquid crystalline solutions. The layers of orderedpolymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended onthe polymerization temperature and the concentration of the solution before polymerization.The cholesteric structure in the composites could not be changed when temperature was lower than 100℃.Cross-linking of the PAA in composites improved their water-resistance.The cholesteric order of the composites without cross-linking was destroyed when they where immersed in water.The color derived from the selective reflection of the cholesteric phase of the cross-linked composites turned from blue to red after the composites absorbed water.The color of the composites could be returned to the original one when the absorbed water was removed from the swollen composites.