A Bioinspired Mineral Hydrogel as a Self‐Healable, Mechanically Adaptable Ionic Skin for Highly Sensitive Pressure Sensing

Abstract

In the past two decades, artificial skin-like materials have received increasing research interests for their broad applications in artificial intelligence, wearable devices, and soft robotics. However, profound challenges remain in terms of imitating human skin because of its unique combination of mechanical and sensory properties. In this work, a bioinspired mineral hydrogel is developed to fabricate a novel type of mechanically adaptable ionic skin sensor. Due to its unique viscoelastic properties, the hydrogel-based capacitive sensor is compliant, self-healable, and can sense subtle pressure changes, such as a gentle finger touch, human motion, or even small water droplets. It might not only show great potential in applications such as artificial intelligence, human/machine interactions, personal healthcare, and wearable devices, but also promote the development of next-generation mechanically adaptable intelligent skin-like devices.

Using Artificial Skin Devices as Skin Replacements: Insights into Superficial Treatment

“…A dielectric layer is sandwiched between two hydrogel layers to form a capacitive sensing mechanism. Reproduced with permission . Copyright 2017, John Wiley and Sons.…”

Nanoparticle–Polymer Synergies in Nanocomposite Hydrogels: From Design to Application

“…A sensor is a device that responds in a distinctive manner after receiving a signal or stimulus (strain, light, or biological elements). In contrast to actuators, strain sensors can convert mechanical energy into other types of energy, such as electrical and optical signals . The excellent mechanical properties and multiple stimuli‐responsive properties of NC gels make them ideal materials for sensors.…”

“…The excellent mechanical properties and multiple stimuli‐responsive properties of NC gels make them ideal materials for sensors. For example, a novel bioinspired physically cross‐linked PAA/aliginate/calcium carbonate NC gel was prepared as a capacitive ionic skin sensor . This NC gel‐based pressure sensor was constructed by integrating two hydrogel films with a dielectric layer.…”

“…a) Schematic design and real‐time capacitance signals of PAA/amorphous calcium carbonate NC gels in the process of finger motion (bent and straight). Reproduced with permission . Copyright 2017, Wiley‐VCH.…”

Self-Healing and Damage Resilience for Soft Robotics: A Review

“…A common thread among recent examples is the use of metal ions as a key to both the self-healing chemistry and the conductive element (Darabi et al, 2017;Lei et al, 2017;Liu and Li, 2017;. Though adding metal ions increases the conductivity of the hydrogels, researchers have carefully tuned the concentration: too low and the hydrogel does not conduct, too high and either the flexibility of the hydrogel is reduced or it ceases to self-heal.…”