Polyaniline-coated cotton knitted fabric for body motion monitoring

Abstract

With the development of wearable sensing technology, increasing attention has been given to flexible wearable sensors with textile structures. With a change in the coil structure, conductive knitted fabric can show satisfactory strain sensing performance and can be used to monitor human activities and physical signs. In this paper, polyaniline (PANI)/cotton conductive knitted fabric was prepared via the deposition of a PANI conductive layer on the fabric surface via in situ polymerization of aniline. The surface morphology, chemical structure, electrical conductivity and mechanical properties of the conductive knitted fabric were investigated, and a flexible fabric strain sensor was fabricated with the conductive knitted fabric as a sensing element. In addition, the sensor is applied to monitor the state of human activity/signs. The results demonstrate that the resistivity of the conductive knitted fabric is reduced by more than 8 orders of magnitude compared with the untreated cotton fabric to 0.275 × 103 Ω cm The conductive knitted fabric shows satisfactory strain sensing performance with high linearity and a maximum gauge factor of more than 30. The strain influences the sensing repeatability of conductive knitted fabric. If the strain is less than 10 %, the repeatability is satisfactory, and if the strain increases to 20 %, the repeatability decreases. Through an analysis of the resistance change of the fabric sensor during the movement of parts of the human body, such as elbows, knees, fingers, and the throat, the sensor shows satisfactory performance in monitoring human movement and physical signs.