Novel Color Changing pH Sensors Based on Cholesteric Polymers

Abstract

Color changing cholesteric hydrogen bonded polymer films responding to pH changes induced by basic amino acids or inorganic bases were synthesized and studied. The films with a higher concentration of donor/acceptor groups display a larger shift of the selective reflection band and faster response. This effect is explained in terms of the breakage of hydrogen bonds that occurs between the components of a cholesteric polymer, immersed in various basic aqueous solutions including amino acids.