Multiple stimuli-switchable electrocatalysis and logic gates of rutin based on semi-interpenetrating polymer network hydrogel films

Abstract

Based on semi-interpenetrating polymer network (semi-IPN) hydrogel films, a multiple stimuli-responsive film system composed of poly(acrylic acid) (PAA) and N,N-diethyl acrylamide (DEA), designated as PAA–PDEA semi-IPN films, was realized on a glassy carbon (GC) electrode surface with a one-step polymerization method. Rutin (RT), an electroactive probe, displayed invertible pH-, thermo- and SO₄²⁻ concentration–sensitive cyclic voltammogram (CV) behaviors in the film system. This multiply sensitive electrocatalysis of RT at the PAA–PDEA films was employed to further investigate the multiple stimuli-responsive ON–OFF behaviors of RT. The scanning electron microscopy (SEM) images and control experiments showed pH-sensitive ON–OFF properties of RT, which could be ascribed to the protonated/deprotonated carboxylic (–COOH) groups of the PAA component in different pH buffers and the properties of RT itself. However, the confirmation change or phase transition of the PDEA hydrogel film between the coil and globular states led to thermo- and SO₄²⁻ concentration–sensitive ON–OFF properties. According to these results, a 3-input/3-output logic gate and a 2-to-1 encoder were constructed successfully. This present system was fabricated for the first time, which may offer numerous possibilities for the design of new electrochemical drug sensors, drug-mimicking release processes and other medical applications. Furthermore, it also can contribute to the development of biomolecular or molecular computing.