Antiliquid-Interfering, Antibacteria, and Adhesive Wearable Strain Sensor Based on Superhydrophobic and Conductive Composite Hydrogel

Underwater adhesion plays an essential role in soft electronics for the underwater interface. Although hydrogel-based electronics are of great interest, because of their versatility, water molecules prevent hydrogels from adhering to substrates, thus bottlenecking further applications. Herein, inspired by the barnacle proteins, MXene/PHMP hydrogels with strong repeatable underwater adhesion are developed through the random copolymerization of 2-phenoxyethyl acrylate, 2-methoxyethyl acrylate, and N-(2-hydroxyethyl) acrylamide with the presence of MXene nanosheets. The hydrogels are mechanically tough (elastic modulus of 32 kPa, fracture stress of 0.11 MPa), and 2-phenoxyethyl acrylate (PEA) with aromatic groups endows the hydrogel with nonswelling property and prevents water molecules from invading the adhesive interface, rendering the hydrogels an outstanding adhesive behavior toward various substrates (including glass, iron, polyethylene terephthalate (PET), porcine). Besides, dynamic physical interactions allow for instant and repeatable underwater adhesion. Furthermore, the MXene/PHMP hydrogels exhibit a high conductivity (0.016 S/m), fast responsiveness, and superior sensitivity as a strain sensor (gauge factor = 7.17 at 200%–500% strain) and pressure sensor (0.63 kPa–1 at 0–70 kPa). The underwater applications of bionic hydrogel-based sensors have been demonstrated, such as human motion, pressure sensing, and holding objects. It is anticipated that the instant and repeatable underwater adhesive hydrogel-based sensors extend the underwater applications of hydrogel electronics.

Section: Introductionmentioning

confidence: 99%

Bio-Inspired Instant Underwater Adhesive Hydrogel Sensors

Guo

Sun

et al. 2022

“…The evolution of flexible and stretchable electronic devices, which either perform human functions or interface with clothing, would significantly change people’s lives by bridging the gap between humans and machines. − Successful examples consist of artificial skins, wearable sensors, flexible optoelectronic devices, and stretchable energy storage devices. , All the abovementioned applications require materials that are conductive, self-healable, biocompatible, and highly sensitive to external deformations. − As compared with traditional nonstretchable materials, intrinsically stretchable conductive materials (e.g., conductive polymers with tailored molecular structures or liquid metal-embedded elastomers) are highly desired. − In view of persistent application issues in electronic devices, self-healing hydrogels with superior ionic conductivity have been recognized as one of the most decent candidates. − …”

Section: Introductionmentioning

confidence: 99%

Self-Healing and Antibacterial Essential Oil-Loaded Mesoporous Silica/Polyacrylate Hybrid Hydrogel for High-Performance Wearable Body-Strain Sensing

Liu

et al. 2022

Flexible electronics have aroused great interest over the past few years due to their unique advantages of being wearable and lightweight. Introducing the self-healing function into wearable electronics will contribute to the practical applications of wearable electronics by prolonging the devices’ lifetime. In this study, a flexible essential oil (EO)-loaded mesoporous silica (EO@AMS)/polyacrylate hybrid hydrogel with superb self-healing and antibacterial properties was prepared. The prepared hybrid hydrogel was found to have excellent piezoresistive sensing performance, which could be particularly suitable for human vital activity monitoring. Benefiting from the strong ionic bonding and multiple hydrogen bonds between polyacrylate and EO@AMS, the hybrid hydrogel could repair its damaged areas with restored sensing and mechanical properties, which suggested excellent self-healing ability. In addition, this hybrid hydrogel, when applied in wearable devices, was found to have high antibacterial ability owing to the slow release of the lemon EO from AMS to kill bacteria. This promising self-healing and antibacterial hybrid hydrogel shows a promising application in wearable electronics for posture monitoring, human–computer interaction, and artificial intelligence.

“…The colonization of bacteria in hydrogels would cause health hazards such as skin abrasion, tissue inflammation, or even infections . Hence, antibacterial property is one of the key prerequisites to improve the safety and service life of bioelectronics. − In addition to ensuring good antibacterial activity, the conductivity stability of hydrogels should also be considered. , As a good metal conductor, silver possesses high electronic conductivity and excellent antibacterial properties. − Zhao et al fabricated a conductive hydrogel composed of polydopamine-coated silver nanoparticles (AgNPs), polyvinyl alcohol (PVA), and polyaniline . The addition of AgNPs endowed the hydrogel with excellent antibacterial properties.…”

Section: Introductionmentioning

confidence: 99%

Motion Detecting, Temperature Alarming, and Wireless Wearable Bioelectronics Based on Intrinsically Antibacterial Conductive Hydrogels

Wang

Song

Liu

et al. 2022

Hydrogels have attracted considerable interest in developing flexible bioelectronics such as wearable devices, brain−machine interface products, and health-monitoring sensors. However, these bioelectronics are always challenged by microbial contamination, which frequently reduces their service life and durability due to a lack of antibacterial property. Herein, we report a class of inherently antibacterial conductive hydrogels (ACGs) as bioelectronics for motion and temperature detection. The ACGs were composed of poly(N-isopropylacrylamide) (pNIPAM) and silver nanowires (AgNWs) via a two-step polymerization strategy, which increased the crosslink density for enhanced mechanical properties. The introduction of AgNWs improved the conductivity of ACGs and endowed them with excellent antibacterial activity against both Gram-positive and -negative bacteria. Meanwhile, pNIPAM existed in ACGs and exhibited a thermal responsive behavior, thereby inducing sharp changes in their conductivity around body temperature, which was successfully employed to assemble a temperature alarm. Moreover, ACG-based sensors exhibited excellent sensitivity (within a small strain of 5%) and the capability of capturing various motion signals (finger bending, elbow bending, and even throat vibrating). Benefiting from the superiority of ACG-based sensors, we further demonstrated a wearable wireless system for the remote control of a vehicle, which is expected to help disabled people in the future.