Development of flexible tactile sensor based on contact resistance of integrated carbon nanotubes

Abstract

We have developed a novel three dimensional tactile sensor based on vertically aligned carbon nanotubes. The carbon nanotubes were directly synthesized on silicon microstructures and these CNTs-on-microstructures were integrated to flexible polydimethylsiloxane layers. Each tactile sensor has four sensing parts and the direction of force can be detected by monitoring the increase or decrease of electrical resistance in each sensing part. High gauge factor up to 272 and fast response less than 10 ms have been experimentally verified from the presented tactile sensor. The deviated contact resistance change from the initial value was less than 3% after repeated force input of 15 mN for 180,000 cycles.

Multidirectional flexible force sensors based on confined, self-adjusting carbon nanotube arrays

“…Then, the growth of vertically aligned CNTs (VACNTs) was carried out for 15 min. As reported previously [31][32][33][34][35], when two sets of growing VACNT arrays meet each other at the middle of the confined space, the strong van der Waals force between the CNT arrays and low bending strength of CNTs prevent further growth of the CNT arrays and their penetration into the CNT arrays on the opposite side.…”

“…Figure 5 shows fabrication process including the pattering of silicon electrodes, growth of CNTs, and their assembly with the PDMS layers [31]. The bump layer, the flexible substrate, and the CNTs-integrated microstructures were separately fabricated and assembled.…”

Piezoresistive flexible composite for robotic tactile applications

“…Therefore, in the present work we have adopted a distributed array of sensors, being this architecture for the above mentioned requirements, the most similar to the human tactile sensing [10]. Piezoelectric [11,12], optical [12], magnetic [13], piezoresistive [2,14], and capacitive [15][16][17] principles are generally reported in the literature [18,19] as working mechanisms for tactile sensing, thus able to transduce the strain or the induced stress, due to a tactile interaction, into an electric signal. Here we have exploited the piezoresistive working principle, since it can fulfill the requirements listed above for the distributed tactile sensing-skin when adopted for polymeric composite materials.…”