Eco-Friendly, Self-Healing Hydrogels for Adhesive and Elastic Strain Sensors, Circuit Repairing, and Flexible Electronic Devices

Abstract

Intelligent skinlike materials have recently attracted tremendous research interests for employing in electronic skin, soft robotics, and wearable devices. Because the traditional soft matters are restricted in unsatisfactory mechanical performances or short-term usage, these materials are adverse to practical applications. Here, intriguing conductive hydrogel materials with multifunctionality (MFHs) are fabricated by using poly­(acrylic acid) (PAA), dopamine-functionalized hyaluronic acid (DHA), and Fe3+ as ionic cross-linker. The mussel-inspired networks with delicate combination of physical and chemical cross-linking possess synergistic features of inherent viscoelasticity, high stretchability (800%), and durable self-adhesiveness to various substrates. Owing to the abundant hydrogen bonds and multiple metal coordination interactions between Fe3+, catechol, and carboxylic groups, the matrix reveals repeatable thermoplasticity and autonomous self-healing property both mechanically and electrically (98% recovery in 2 s). When served as strain sensors, the MFHs can distinctly perceive complex body motions from tiny physiological signal (breathing) to large movements (knee bending) as human motion detecting devices. Moreover, the MFHs were explored as ideal material for circuit repairing, programming, and switches constructing because of their excellent properties. Consequently, these eco-friendly hydrogel ionotronic devices can be promising candidates for next-generation intelligent wearable devices and human–machine interfaces.

Fabrication of alginate‐P(SBMA‐co‐AAm) hydrogels with ultrastretchability, strain sensitivity, self‐adhesiveness, biocompatibility, and self‐cleaning function for strain sensors

“…To verify this capability, the resistance variations of 6ASAm versus strains (tensile strain: 0%–300%; compressive strain: 0%–80%) were recorded using a DC resistance meter. When the hydrogel was stretched, the tunneling of ionic pathway elongated and the cross‐sectional area of hydrogel shrank, 37 resulting in the restriction of ion transport and increment of resistance. On the contrary, once the hydrogel was compressed, the resistance decreased.…”

PAANa-induced ductile SEI of bare micro-sized FeS enables high sodium-ion storage performance

“…1f, g. In the FT-IR spectroscopy (Fig. 1e) loose network to fix iron sulfide particles is maintained [56]. The network structure of the FeS-PAANa electrode helps in buffering the stress caused by the volume changes and keeping the composites of electrode closely in contact.…”

A review of flexible force sensors for human health monitoring

“…Zhang et al [78] synthesized a multifunctional conductive hydrogel with the polyacrylic acid, dopamine-functionalized hyaluronic acid and Fe 3+ . The substrate exhibited mechanically and electrically repeatable, thermoplastic and self-healing properties (98% recovery within 2 s).…”