All-polymer hair structure with embedded three-dimensional piezoresistive force sensors

This paper presents the design, fabrication, and experimental demonstration of an artificial hair sensor made of polymer materials. Long polymer hair structures embedded with flexible three-dimensional piezoresistive sensors were formed on a flexible substrate in two-dimensional arrays to detect an applied external force. The flexible piezoresistor was implemented using a carbon nanotube-polydimethylsiloxane (CNT-PDMS) composite prepared by the mixing of multi-wall carbon nanotubes with PDMS. A CNT-PDMS composite with high conductivity and a high gauge factor was obtained by increasing the CNT concentration in PDMS. In this study, we used a 13% CNT-PDMS composite for fabricating the sensing element that was embedded in the proposed hair sensor. The hair sensor is 4 mm in height and 700 μm in diameter. The implemented device shows a linear and sensitive response in the on-axis mode with a sensitivity of 2900 ppm/μm.