Electrochemically Synthesized Polyaniline Nanofibers on Flexible Electrode for pH Sensing

Artikel i vetenskaplig tidskrift, 2026

pH monitoring is essential in diverse fields such as clinical diagnostics, environmental surveillance, food quality control, and industrial process management. Wound exudate pH serves as a noninvasive biomarker of wound status. Here, we report a flexible electrochemical pH sensor based on polyaniline nanofiber (PANI NF) modified polyimide electrodes prepared by electrochemical deposition. The nanofibrous PANI layer exhibits a porous interconnected architecture, as confirmed by scanning electron microscope (SEM), Fourier transform infrared (FTIR), Raman, and X-ray photoelectron spectroscopy (XPS) analyses. The PANI NF electrode displayed a near-Nernstian sensitivity of 57 mV pH⁻¹ over the pH 5–9 range with excellent linearity (R² > 0.99), low hysteresis (<4 mV), and high reproducibility (RSD 0.54%). Long-term drift studies revealed minimal potential drift (<1 mV h⁻¹), and the calibration slope remained unchanged after 5 days of floating. The sensor accurately measured the pH of serum-containing simulated wound fluid (SWF), with deviations ≤ 0.06 from a commercial glass-electrode pH meter. After 90 days of storage at 4°C in the dark, the sensor retained its sensitivity with only minor variability (RSD 2.77%). These results demonstrate that the flexible PANI based sensor offers fast response, high sensitivity, and excellent stability, making it a promising platform for real-time, continuous monitoring of wound exudate pH and other biomedical or environmental applications.