Materials chemistry approach to anion-sensor design

A new approach to sensing of aqueous phosphate-related anions based on chromogenic conductive polymers is demonstrated. The anion-sensor affinity can be adjusted by externally applied voltage. Introduction of p-doping to the polymers results in augmented anion sensitivity, which is ascribed to the effect of synergy between low-level p-doping in a polythiophene polymer and hydrogen bonding. The chromogenic conductive polymer films display anion-specific changes in color, conductivity, and mass upon increasing concentration of anions.