Waterproof and Flexible Aquatic Tactile Sensor with Interlocked Ripple Structures for Broad Range Force Sensing

Abstract

Underwater perception of a broad range of force holds great importance in aquatic explorative activities, while flexible tactile sensors face technical challenges to realize. This paper presents a novel flexible aquatic tactile sensor based on waterproof graphene (GR)/carbon nanotube (CNT)/Polydimethylsiloxane (PDMS) composites. The prepared GR/CNT/PDMS composites possess excellent hydrophobic and electromechanical properties with a water contact angle over 134° and an ultrahigh gauge factor of 2296, making them an ideal piezoresistive sensing material for underwater broad‐range force sensing. The proposed tactile sensor has 3 × 3 sensing units and uses dual interlocked water‐ripple structures to improve its sensitivity and force detection range. The fabricated tactile sensor is characterized by two distinct sensitivities: a high sensitivity of 0.0338 kPa−1 at 0.062–150 kPa and a low sensitivity of 0.00357 kPa−1 at 150–450 kPa. Further, the sensor exhibited excellent resistance response, fast dynamic recovery, and both mechanical and electrical stability in aquatic environments. Then, the aquatic tactile sensor is worn on the palm of the human hand to detect the distribution and variation of contact forces when grasping objects with different shapes and hardness, demonstrating the potential underwater applications of the developed aquatic tactile sensor for broad‐range force sensing.

Recent Progress in 3D Printing of Polymer Materials as Soft Actuators and Robots

“…13−17 Among these soft materials, hydrogels, shape memory polymers, and liquid crystalline elastomers have received increasing attention due to the versatile properties and functions. 3,9,13,18,19 These polymeric materials not only enable flexible design at macroscopic scales but also offer tailored functionalities by design at molecular and network levels. 20−23 Moreover, some specific functionalities, such as self-healing ability and degradability that hard materials rarely have, may increase the lifetime and sustainability of the soft robots and actuators, making them more close to biological organisms.…”

“…Their basic mechanical properties, processability, and biocompatibility are studied and compared with biological tissues . These soft materials with a high degree of design flexibility and rich stimulus-responsive characteristics favor the fabrication of soft robots to better mimic the structures of living organisms and perform a variety of complex actions. − Among these soft materials, hydrogels, shape memory polymers, and liquid crystalline elastomers have received increasing attention due to the versatile properties and functions. ,,,, These polymeric materials not only enable flexible design at macroscopic scales but also offer tailored functionalities by design at molecular and network levels. − Moreover, some specific functionalities, such as self-healing ability and degradability that hard materials rarely have, may increase the lifetime and sustainability of the soft robots and actuators, making them more close to biological organisms. − …”