Biochar-Enhanced Textile-Based Piezoresistive Sensors for Real-Time Flow and Pressure Monitoring in Fluidic Systems

Progress in flexible piezoresistive sensors is essential for applications in wearable technologies and real-time fluid monitoring systems. This study presents the fabrication and performance of textile-based sensors coated with Senna siamea biomass–derived biochar at different loadings via a dip-coating technique. Biochar structural and surface characteristics were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Sensors with biochar loadings of 1, 5, 10, and 15 wt % were integrated into a custom-designed flow setup to examine the evolution of their electrical resistance under varying water flow rates and applied pressures. Sensors with low biochar loadings, particularly 5 wt %, demonstrated superior sensitivity, stability, and linearity, showing distinct resistance variations corresponding to pressure changes induced by water flow. Higher biochar contents resulted in agglomeration and reduced conductivity, thereby diminishing sensor performance. The sensors exhibited reliable output under both static and dynamic conditions, thus holding promise for wearable health monitoring and industrial fluid control. This work shows the potential of biochar as a sustainable and cost-effective material for next-generation piezoresistive sensing platforms.