Highly Sensitive Pressure Sensor Using Two-Dimensionally Aligned Carbon Nanotube Bundles

A highly sensitive two-dimensional tactile sensor has been developed by applying the stain-induced change of the electronic resistance of MWCNTs (Multi-Wall Carbon Nano-Tubes). The elastic deformation of a bundle of MWCNTs was confirmed under the axial compressive strain from 0% to 60%, and the sensitivity of compressive force was 1 mN. The maximum gauge factor of the bundle under the compressive strain was about 100, and it was obtained from the buckling deformation of the bundle. Since the effective elastic constant of the bundle was about 140 kPa, it was important to use a very soft dielectric material for electrical isolation among area-arrayed fine bundles in the tactile sensor. The application of polydimethylsiloxane (PDMS) was found to be effective for assuring the flexible deformation of each bundle in the sensor under the application of a distributed load.