Development of a 3D distributed carbon nanotubes on flexible polymer for normal and shear forces measurement

This study reports a simple approach to implement a flexible CNTs tactile sensor to enable the detecting of normal and shear forces. The merits of the presented tactile sensors are as follows, (1) embedded patterned CNTs into polymer using simple Si-substrate molding process, (2) 3D distributed CNTs enable the detection of shear and normal forces, and (3) 3D polymer structure by molding as a tactile-bump. In applications, the CNTs are grown and patterned on bulk-micromachined Si substrate with 3D surface profile. After polymer molding, the 3D distributed CNTs are successfully transferred onto a flexible PDMS with 3D tactile-bump. With proper CNTs pattern designs, the tactile sensor has a sensitivity (linearity) of up to 20.95%/N (R²=0.93) for normal load, and up to 95.24%/N (R²=0.95) for shear load.