Facile Fabrication of 3D Porous Sponges Coated with Synergistic Carbon Black/Multiwalled Carbon Nanotubes for Tactile Sensing Applications

Abstract

Recently, flexible tactile sensors based on three-dimensional (3D) porous conductive composites, endowed with high sensitivity, a wide sensing range, fast response, and the capability to detect low pressures, have aroused considerable attention. These sensors have been employed in different practical domain areas such as artificial skin, healthcare systems, and human–machine interaction. In this study, a facile, cost-efficient method is proposed for fabricating a highly sensitive piezoresistive tactile sensor based on a 3D porous dielectric layer. The proposed sensor is designed with a simple dip-coating homogeneous synergetic conductive network of carbon black (CB) and multi-walled carbon nanotube (MWCNTs) composite on polydimethysiloxane (PDMS) sponge skeletons. The unique combination of a 3D porous structure, with hybrid conductive networks of CB/MWCNTs displayed a superior elasticity, with outstanding electrical characterization under external compression. The piezoresistive tactile sensor exhibited a high sensitivity of (15 kPa−1), with a rapid response time (100 ms), the capability of detecting both large and small compressive strains, as well as excellent mechanical deformability and stability over 1000 cycles. Benefiting from a long-term stability, fast response, and low-detection limit, the piezoresistive sensor was successfully utilized in monitoring human physiological signals, including finger heart rate, pulses, knee bending, respiration, and finger grabbing motions during the process of picking up an object. Furthermore, a comprehensive performance of the sensor was carried out, and the sensor’s design fulfilled vital evaluation metrics, such as low-cost and simplicity in the fabrication process. Thus, 3D porous-based piezoresistive tactile sensors could rapidly promote the development of high-performance flexible sensors, and make them very attractive for an enormous range of potential applications in healthcare devices, wearable electronics, and intelligent robotic systems.

Polydimethylsiloxane Composites Characterization and Its Applications: A Review

“…The piezoresistive sensor has been used successfully in monitoring human physiological signals including finger heart rate, pulses, knee flexion, breathing, and finger gripping movements. The highly sensitive piezo-resistive sensor indicates great potential for applications in robotic-assisted surgery systems, human–machine interfaces, and low-cost wearable health electronics [ 125 ].…”

“… 3D porous sponge made of PDMS, carbon black and carbon nanotube for application in monitoring physiological signals, breathing, gripping movements, and heart rate, adapted from [ 125 ]. …”

A Hybrid Microstructure Piezoresistive Sensor with Machine Learning Approach for Gesture Recognition

“…The sensor fabrication and design processes followed the route proposed in our previous study [32]. Following the sensor characterization results based on its chemical, physical, mechanical, and electrical properties, it was realized that the sensor model is strongly dependent on the material preparation and fabrication process conditions.…”

A Flexible Pressure Sensor with Ink Printed Porous Graphene for Continuous Cardiovascular Status Monitoring

“…Metal nanomaterials such as AgNPs, AgNWs, and AuNWs process high sensitivity, yet their high costs prevent the sensor from having wide-range application [ 17 , 18 , 19 , 20 , 21 ]. Carbon nanotubes (CNT) such as single-wall CNT (SWCNT) and multi-wall CNT (MWCNT) are cheap, but their electromechanical properties are hard to control, which is still a dilemma in large-scale manufacturing [ 22 , 23 ]. On the other hand, the raw material cost of graphene is low, and its performance is stable for the manufacturing procedure, which makes it a desirable material for flexible electronics design.…”