Distinct color changes in hydrogen peroxide-responsive thin films consisting of boronic acid-containing polymers

Abstract

A novel methodology for the preparation of hydrogen peroxide (H2O2)-responsive thin-film sensors that display distinct color changes was developed. Boronic acid-containing films were obtained through the copolymerization of boronic acid and tertiary amine monomers, acrylamide, and a crosslinker on a pattern-printed microscope slide. After immersing the thin films in an aqueous H2O2 solution, they were colored with anionic dye solutions containing fructose. The color of the thin films changed depending on the H2O2 concentration in the solutions. When the H2O2 concentration is low, the thin film adsorbs a cationic dye, whereas at higher H2O2 concentrations, it adsorbs an anionic dye. This indicates that the thin film was negatively charged before reacting with H2O2 and that the charge converted to positive following the reaction with H2O2. Changes in the parameters such as monomer composition, pH, and fructose concentration might affect the color change behavior. The H2O2-responsive thin films presented herein are advantageous for the development of H2O2 sensors because of their relatively simple preparation and non-complex organic synthesis. In addition, there is virtually no limitation to choosing dyes, and any kind of color change can be realized.