Tunable selective reflection of a hydroxypropyl cellulose aqueous solution

Hydroxypropyl cellulose aqueous solution forms a cholesteric liquid crystal phase and is colored by a selective reflection. The color can be changed by applied voltage. Although many tiny bubbles which disturb current conduction are generated at a cathode electrode, it can be suppressed by a current control. A container of the HPC solution affects the selective reflection effect. A HPC solution in a tube is more homogeneous than in a conventional sandwich cell.