MWCNT-coated cotton yarn array for piezoresistive force and bending sensor applications in Internet of Things systems

Advanced sensors based on the Internet of Things (IoT) are bringing new technology and productivity paradigms to the era of the fourth industrial revolution. Here, piezoresistive force and bending sensors with good performance (sensitivity ≈ 0.3 kPa⁻¹ and ∆normalized resistance/∆curvature ≈1.5 cm) were fabricated by using perpendicularly aligned multi-walled (MW) carbon nanotube-coated yarn (CNT-CY) arrays, which were obtained from a simple dipping-and-drying method. Verification was performed using a proof-of-concept force sensor matrix with an Arduino open-source microcontroller. In addition, a force sensor combined with real-time data storage in Google Cloud was successfully demonstrated. This work provides important information for the development of a robust, low-cost, and easy-to-manufacture IoT platform with MWCNT-based composites as an active sensing material.