Textile-Based Capacitive Pressure Sensors Enabled by Ultrasonic Spray-Coated Carbon Black Electrodes and Electrostatic Flocking

Abstract

Textile-based pressure sensors are essential for wearable electronics, but achieving mechanical robustness, high sensing performance, and scalable fabrication remains challenging. A fully textile-integrated capacitive pressure sensor is developed using low-cost materials, comprising ultrasonic spray-coated carbon black (CB) electrodes and electrostatically flocked nylon microfiber dielectric layers on Kevlar substrates. A statistically guided optimization approach, combining Taguchi analysis and response surface methodology, establishes the relationship between deposition parameters and conductive network formation, producing uniform coatings with a sheet resistance of approximately 50 Ω sq⁻¹. The vertically aligned nylon microfibers form a compressible air–fiber dielectric structure that enhances capacitance changes under pressure. The sensor exhibits a sensitivity of 1.05 kPa⁻¹ at low pressure (< 1.5 kPa), low hysteresis (10.1%), and stable performance over 1000 loading cycles. Fabrication is achieved without lithography, elastomers, or nanomaterial ink, providing a simple, scalable, and cost-effective textile-only sensing platform. A 3 × 3 sensor array demonstrates spatial pressure-mapping capability, highlighting potential applications in ergonomic seating, smart safety garments, and the monitoring of ballistic or blast exposure events where puncture resistance is essential.