Tailoring electrochemical sensor performance of CB–PVDF composites through controlled polymer processing methods

Abstract The development of conductive polymer composites is critical for advancing low-cost, flexible electrochemical sensors. In this study, carbon black-polyvinylidene fluoride (CB-PVDF) composites were fabricated using various processing methods, extrusion, injection molding, spin coating, and solution casting, to investigate the relationship between morphology, crystallinity, and electrochemical performance in sensor applications. Structural integrity of the PVDF matrix was confirmed via NMR spectroscopy, with FTIR and Raman analyses revealing the presence of multiple crystalline phases and minor spectral shifts due to carbon black addition. Thermal analysis via TGA and DSC showed high thermal stability across all composites, with degradation temperatures remaining above 430 °C and crystallinity varying by processing method. Scanning electron microscopy (SEM) revealed significant differences in carbon black dispersion, with solution-processed films demonstrating more uniform distribution compared to thermally processed samples. Electrochemical sensor analysis using cyclic voltammetry (CV) indicated that sanded extruded CB-PVDF fibers exhibited the highest electroactive surface area (23.8 m2/g) and the most consistent redox activity across a range of solvents, outperforming injection molded and solution cast films. These results highlight the critical role of processing in tailoring composite properties and identify sanded extruded CB-PVDF fibers as a promising platform for high-performance electrochemical sensor applications.