Electroactive Flexible Sensor for Selective L-Ascorbic Acid Detection Using Polyaniline-Decorated Phosphotungstic Acid/Copper Composite

In this study, we spotlight a flexible stainless steel (FSS)- based hybrid electrode with phosphotungstic acid-copper-embedded poly(aniline) (FSS/PANI/PTA/Cu) composite for the efficient detection of L- ascorbic acid (AA). Single pot electrodeposition has been engaged in fabricating PANI/PTA/Cu composite on FSS via cyclic voltammetry(CV). The successful composite fabrication has been authenticated through physicochemical characterization, including its structural geometry, surface morphology, and molecular vibrational properties, which were analyzed through X-ray crystallography (XRD), field emission scanning electron microscopy (FESEM), infrared spectroscopy (FTIR) and UV-Vis spectrophotometers. The electrochemical sensing performances were examined using CV and chronoamperometric analysis (CA). The flexible sensor measured a sensitivity of 3.79 mA/mM with a detection limit (LOD) of 7.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>M for AA. This performance results from the combined synergetic action of PANI, PTA, and Cu, which enabled efficient ionic diffusion and seamless electron transfer through a high density of accessible electroactive sites. Additionally, the flexible sensor electrode exhibited remarkable selectivity for AA, with negligible interference from co-existing species, highlighting its potential for healthcare diagnostic applications in near future.