Breathable and Waterproof Electronic Skin with Three-Dimensional Architecture for Pressure and Strain Sensing in Nonoverlapping Mode

Abstract

Wearable sensors have recently attracted extensive interest not only in the field of healthcare monitoring but also for convenient and intelligent human–machine interactions. However, challenges such as wearable comfort, multiple applicable conditions, and differentiation of mechanical stimuli are yet to be fully addressed. Herein, we developed a breathable and waterproof electronic skin (E-skin) that can perceive pressure/strain with nonoverlapping signals. The synergistic effect from magnetic attraction and nanoscaled aggregation renders the E-skin with microscaled pores for breathability and three-dimensional microcilia for superhydrophobicity. Upon applied pressure, the bending of conductive microcilia enables sufficient contacts for resistance decrease, while the stretching causes increased resistance due to the separation of conductive materials. The optimized E-skin exhibits a high gauge factor of 7.747 for small strain (0–80%) and a detection limit down to 0.04%. The three-dimensional microcilia also exhibit a sensitivity of −0.0198 kPa–1 (0–3 kPa) and a broad detection range up to 200 kPa with robustness. The E-skin can reliably and precisely distinguish kinds of the human joint motions, covering a broad spectrum including bending, stretching, and pressure. With the nonoverlapping readouts, ternary inputs “1”, “0”, and “–1” could be produced with different stimuli, which expands the command capacity for logic outputs such as effective Morse code and intuitive robotic control. Owing to the rapid response, long-term stability (10 000 cycles), breathability, and superhydrophobicity, we believe that the E-skin can be widely applied as wearable devices from body motion monitoring to human–machine interactions toward a more convenient and intelligent future.

Flat Silk Cocoon Pressure Sensor Based on a Sea Urchin-like Microstructure for Intelligent Sensing

“…It is speculated that the possible reason is that the increase in the interval of spraying HMSFP reduces the number of FSC layers formed, resulting in a smaller contact distance between the conductive layers on the surface of the FSC. When the external contact pressure changes, the sample with a smaller distance between the conductive layers can respond to the pressure signal in a shorter time, , and the number of conductive paths will reach saturation faster. Therefore, there will be a phenomenon that the sensitivity and the pressure detection range have opposite trends.…”

Functional microneedles for wearable electronics

“…poly (3,4ethylenedioxythiophene): poly(styrenesulfonate), 67 gold nanowires, 68 MXene nanoflakes 69 and carbon black 70 ) or mingled with conductive substances (e.g. carbon nanotube, 71 carbon black 72 and nano-copper 72 ) is usually used to constitute the microneedle-like layers. Up to now, researchers have applied the resistance-based sensors to monitor wrist pulse, 68 recognize voice, 69 detect body movements 72 and so on.…”

“…For example, a microneedleintegrated electronic skin was presented for sensing both pressure and strain forces (Figure 4A). 71 When pressure F I G U R E 3 Wireless microneedle-integrated sensing system for electrochemically detecting metabolites of human subjects. (A) Schematic and scanning electron microscope (SEM) images of the microneedles.…”

Conjugated Polymer-Based Nanocomposites for Pressure Sensors

“…Flexible sensors have attracted tremendous attention due to their potential applications in the fields of health monitoring, medical diagnosis, electronic skin (e-skin), and artificial intelligence [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. In recent years, flexible sensors have made great progress in material selection, structure design, and practical application [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ].…”