Development of Polydimethylsiloxane (PDMS) Functionalized MWCNT Based Flexible Pressure Sensors for Tactile Sensing

Through this work, polydimethylsiloxane (PDMS) functionalized multiwall carbon nanotubes (fMWCNT) flexible tactile sensors, referred as PDMS-fMWCNT have been explored. These sensor elements are designed to further assist a robotic arm to carry out basic activities such as object gripping and slip detection, which would be armed further with sensor arrays, electronic interface and machine-learning algorithms. The response of PDMS-f-MWCNT is compared to the basic PDMS, and the composite shows better response with higher resolution when measuring change in resistance. Structural characterization shows active hydroxyl groups for f-MWCNTs. With changing percentage of MWCNT (1% to 5%), the percolation threshold was achieved at 2%, which showed the optimized piezoresistive response where the maximum change in resistance was 2.79 MΩ. The sensor with 4% doping showed the optimal linear behavior among all sensors with different doping concentrations. The sensor shows good response time (0.36 s) and recovery time (0.24 s) for 5 rad/s of impact frequency. All the sensors had 2mm * 2mm * 4mm dimensions and were highly porous. The fine interplay between the MWCNT percentage, the basic sample resistivity and the sample recovery resulting in the pressure-handing capacity of the samples show that the optimized sample could work as an excellent tactile sensor for multiple applications ranging from robotic industry to healthcare gadgets.