Fishing Net‐Inspired Mutiscale Ionic Organohydrogels with Outstanding Mechanical Robustness for Flexible Electronic Devices

Abstract

Mechanically robust and electrically conductive organohydrogels/hydrogels are increasingly required in flexible electronic devices, but it remains a challenge to achieve organohydrogels/hydrogels with integrated high performances. Herein, inspired by the geometric deformability and robustness of fishing nets, multiscale ionic organohydrogels with outstanding isotropic mechanical robustness are developed. The organohydrogels are prepared by introducing polyacrylamide (PAM) hydrogel, Zn2+ and a binary solvent of glycerol‐water into a crosslinked fibrous mat which is electrospun from poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA). Because of the unique structure, the resultant organohydrogels, being mentioned as PAA‐PVA/PAM/Zn2+ organohydrogels, exhibit outstanding tensile strength (9.45 MPa), high stretchability, excellent anti‐fatigue property, skin‐like mechanical behaviors and ionic conductivity. Importantly, the organohydrogels are promising in flexible electronic devices capable of operating properly over a wide temperature range and under harsh mechanical conditions, such as mechanical‐electrical signal transducing materials in flexible mechanosensors and robust electrolytes in zinc ion hybrid supercapacitors. Not only the multiscale design strategy will provide a clue to improve the mechanical properties of soft materials, but also the organohydrogels offer promising materials for future flexible electronic devices.

Stable Flexible Electronic Devices under Harsh Conditions Enabled by Double-Network Hydrogels Containing Binary Cations

“…In a current density range of 0.5–10 A·g –1 , symmetrical quasi-triangular GCD curves were recorded, indicating the reversible charge–discharge ability of supercapacitors (Figure S6d). ,, …”

“…In a current density range of 0.5−10 A•g −1 , symmetrical quasi-triangular GCD curves were recorded, indicating the reversible charge−discharge ability of supercapacitors (Figure S6d). 6,14,51 Because binary cations endow hydrogel electrolytes with excellent environmental adaptability, the supercapacitors can work properly under subzero conditions. Figure 6b,c shows the CV curves and GCD curves of a supercapacitor containing H 1,3 as the electrolyte at different temperatures.…”

“…Ionic hydrogels, which are composed of cross-linked polymer networks, with a large amount of water and ions, are increasingly explored in fabricating flexible electronic devices due to their combined soft nature and ion transportation ability. − Mechanical robustness is critical to maintain the stability and integrity of ionic hydrogels under long-term mechanical loading. , Given the composition of hydrogels, the on-demand regulation of mechanical properties of hydrogels is mainly achieved by controlling the structures of polymer chains, cross-linking points, and water contents. Most approaches have been developed to construct mechanically robust hydrogels by various network structure designs, such as double network (DN), , dually cross-linked network, topological network, , nanocomposite network, etc.…”

Highly Stretchable, Fast Self-Healing, Self-Adhesive, and Strain-Sensitive Wearable Sensor Based on Ionic Conductive Hydrogels

“…The strain factor (GF = Δ R / R 0 /ε, where ε represents the applied strain) was calculated from the change in relative resistance. In addition, the slope of the strain curve can be used to estimate the sensitivity of the wearable hydrogel sensor. , As shown in Figure e, the sensitivity of the hydrogel sensor increases with the increase of strain. The resistance of the hydrogel-based sensors shows a short response/recovery time (0.54/0.31 s), as shown in Figure f.…”

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

“…Natural multi-scale micro-nano structures have attracted increasingly more attention from material designers. 31–36 For example, artificial muscle contains multi-fiber proteins, which can provide high strength and toughness. 37–39 Inspired by this, a strategy is proposed for nano-polymer segments to penetrate micron hydrogel microspheres as physical cross-linking points to form multi-scale hydrogel networks, which helps improve the mechanical properties of the hydrogel.…”