Bioinspired Tactile Sensation Based on Synergistic Microcrack-Bristle Structure Design toward High Mechanical Sensitivity and Direction-Resolving Capability

Abstract

Natural tactile sensation is complex, which involves not only contact force intensity detection but also the perception of the force direction, the surface texture, and other mechanical parameters. Nevertheless, the vast majority of the developed tactile sensors can only detect the normal force, but usually cannot resolve shear force or even distinguish the directions of the force. Here, we present a new paradigm of bioinspired tactile sensors for resolving both the intensity and the directions of mechanical stimulations via synergistic microcrack-bristle structure design and cross-shaped configuration engineering. The microcrack sensing structure gives high mechanical sensitivity to the tactile sensors, and the synergistic bristle structure further amplifies the sensitivity of the sensors. The cross-shaped configuration engineering of the synergistic microcrack-bristle structure further endows the tactile sensors with good capability to detect and distinguish the directions of the applied mechanical forces. The as-fabricated tactile sensors exhibit a high sensitivity (25.76 N −1 ), low detection limit (5.4 mN), desirable stability (over 2,500 cycles), and good capability to resolve both mechanical intensity and directional features. As promising application scenarios, surface texture recognition and biomimetic path explorations are successfully demonstrated with these tactile sensors. This newly proposed tactile sensation strategy and technology have great potential applications in ingenious tactile sensation and construction of various robotic and bionic prostheses with high operational dexterity.

Materials-Driven Soft Wearable Bioelectronics for Connected Healthcare

“…A cracked elastomer or nano-/microcrack has been intentionally generated on elastomers to bring ultrasensitivity for subtle strain detection. − The disconnection/reconnection between adjacent zip-like nanoscale crack junctions enabled sensitive resistivity responses to external mechanical stimuli achieving extremely large gauge factor and low signal-to-noise ratio (SNR) . The mechanical crack-based strain sensor was first inspired by the spider sensory system with a slit organ geometry .…”

“…245−249 The disconnection/reconnection between adjacent zip-like nanoscale crack junctions enabled sensitive resistivity responses to external mechanical stimuli achieving extremely large gauge factor and low signalto-noise ratio (SNR). 250 The mechanical crack-based strain sensor was first inspired by the spider sensory system with a slit organ geometry. 251 The electrical conductance across the stiff and ultrathin (20 nm) sputter-deposited Pt layer could be measured by the controlled cracks (both density and direction) formed by mechanically bending the elastomers under various radii of curvatures.…”

Flexible wide-range multidimensional force sensors inspired by bones embedded in muscle

“…In recent years, with the development of flexible electronics, flexible pressure sensors have shown great potential in motion monitoring 1 – 3 , human‒machine interaction (HMI) 4 – 6 , personalized medicine 7 – 9 , and soft intelligent robots 10 – 12 . Perceiving and detecting multidirectional mechanical stimuli is crucial for pressure sensing and can provide comprehensive, complete, and accurate information about pressure distributions and interactions to realize motion direction detection 13 , slip detection 14 , and grasp detection 15 . Numerous studies have been conducted to achieve multidirectional force response and a wide sensing range in pressure sensors for various applications.…”

Construction of Wearable Touch Sensors by Mimicking the Properties of Materials and Structures in Nature

“…In the construction of the aforementioned wearable touch sensors, a variety of novel materials (e.g., flexible polymers [ 23 ], stretchable elastomers [ 24 ], soft hydrogels [ 25 ], etc.) and unique structures (e.g., pyramid [ 26 ], hemisphere [ 27 ], cylinder [ 28 ], cilia [ 29 ], crack [ 30 , 31 ], etc.) have played an importance role in the enhancement and realization of high sensing performance and unique device functionalities.…”