Transparent, Ultra-Stretching, Tough, Adhesive Carboxyethyl Chitin/Polyacrylamide Hydrogel Toward High-Performance Soft Electronics

Abstract

To date, hydrogels have gained increasing attentions as a flexible conductive material in fabricating soft electronics. However, it remains a big challenge to integrate multiple functions into one gel that can be used widely under various conditions. Herein, a kind of multifunctional hydrogel with a combination of desirable characteristics, including remarkable transparency, high conductivity, ultra-stretchability, toughness, good fatigue resistance, and strong adhesive ability is presented, which was facilely fabricated through multiple noncovalent crosslinking strategy. The resultant versatile sensors are able to detect both weak and large deformations, which owns a low detection limit of 0.1% strain, high stretchability up to 1586%, ultrahigh sensitivity with a gauge factor up to 18.54, as well as wide pressure sensing range (0–600 kPa). Meanwhile, the fabrication of conductive hydrogel-based sensors is demonstrated for various soft electronic devices, including a flexible human–machine interactive system, the soft tactile switch, an integrated electronic skin for unprecedented nonplanar visualized pressure sensing, and the stretchable triboelectric nanogenerators with excellent biomechanical energy harvesting ability. This work opens up a simple route for multifunctional hydrogel and promises the practical application of soft and self-powered wearable electronics in various complex scenes.

A novel multi-scale pressure sensing hydrogel for monitoring the physiological signals of long-term bedridden patients

“…Furthermore, the P 16 AMV-2 hydrogel showed better pressure sensitivity (0.59 kPa À1 ) than the existing hydrogel (0.27-0.40 kPa À1 ). 45,46 The sensor prepared by this hydrogel could also monitor the physiological condition of long-time bedridden patients in real time, successfully solving the problem of caregivers replacing diapers for patients in time to avoid the risk of skin infection. Therefore, the pressure-sensing hydrogel has broad application value in the medical field.…”

Deep-Learning Enabled Active Biomimetic Multifunctional Hydrogel Electronic Skin

“…To mimic this multilayer skin structure, researchers have proposed several types of e-skins with similar functions and properties as the human skin. − The dermis, one of the three main components of human skin, is responsible for keeping the skin supple and elastic and also acting as a fluid reservoir. It also protects the blood capillaries, glands, and other substances in the skin tissue. , Additionally, it generates ion channels in this region, providing absorption channels for moisture and nutrients. − The tactile sense functions of the natural skin were proven to be mostly due to existence of mechanoreceptors within the dermis . Previous e-skin-related studies have been mostly concentrated more on achieving the function of pressure detection, whereas the other functions of the dermis have seldom been achieved in electronic skin. − …”

“…It also protects the blood capillaries, glands, and other substances in the skin tissue. 21,22 Additionally, it generates ion channels in this region, providing absorption channels for moisture and nutrients. 23−25 The tactile sense functions of the natural skin were proven to be mostly due to existence of mechanoreceptors within the dermis.…”

Easy-to-Prepare Flexible Multifunctional Sensors Assembled with Anti-Swelling Hydrogels

“…Hydrogels, which are water-containing flexible and stretchable materials, are considered to be a good candidate for developing flexible electronic devices. In recent years, hydrogels have shown great promise for advanced applications in flexible electronic devices, including soft robots − and wearable sensors. − In particular, hydrogel-based wearable sensors are widely used for health monitoring on the body’s surface − or in vivo, , showing outstanding potential for biomedical applications. In order for hydrogels to be successfully utilized in health monitoring applications, significant progress in the property tuning of hydrogels has been made, including stretchability − and adhesion. − However, hydrogels that are applied as flexible electronic devices still face challenges.…”