Ion Clusters‐Driven Strong and Acid/Alkali/ Freezing‐Tolerant Conductive Hydrogels for Flexible Sensors in Extreme Environments

Abstract

Supramolecular polymer hydrogels, exhibiting wide applications in flexible sensing, wearable electronics, artificial skin, etc., often require complex molecule and component design to adapt extreme environments. Most supramolecular polymer hydrogels currently, however, are unable to satisfy the harsh demands ascribed to their poor mechanical properties and chemical stability. Herein, this study demonstrates a novel strategy to fabricate superstrong polyvinyl alcohol (PVA) hydrogels with densely supramolecular polymer networks (SPNs) and complexation, induced by simple deprotonation and reconfiguration of ion clusters (ICs). Such strategy enables the PVA hydrogels with high strength (9.64 ± 0.5 MPa), compressibility, and recoverability (load objects over ≈10000 times more than its weight), resistance to various solvents, freezing tolerance (keep flexible and conductive even at −50 °C) and many other performances. Notably, the properties of resultant hydrogels surpass majority reported, tackling a long‐standing dilemma both mechanical properties and stability for PVA hydrogels. A proof‐of‐concept spider robot is assembled by 3D printed model, which achieves successfully signal acquisition in different extreme conditions. In this study the multifunctional PVA hydrogels are envisioned as a simple and universal strategy for sensors in various conditions, which is significant for the exploration in extreme environments that are not easily accessible to humans, such as the North and South Poles and solvent leakage area.

Engineering Robust Conductive Hydrogel Sensors with Enhanced Mechanical Properties and Practical Applicability

“…As shown in Figure a,b, the mechanical properties of the PVA-15 hydrogel are remarkably higher than those of PVA-10 hydrogel. This is because as the concentration of PVA solution increases, the number of PVA molecular chains per unit volume in the solution increases; the microcrystalline region formed by the cross-linking of PVA molecular chains themselves also increases after the freeze–thaw cycle, thus enhancing the mechanical properties of the hydrogel . However, when the PVA concentration exceeds 15 wt %, the solution is too vicious to obtain a homogeneous solution.…”

Enhancement of the catalytic performance of UIO-66 for the CO2 synthesis of cyclic carbonate using natural nanomaterials as a carrier

“…In contrast, a redshift of the (1 1 0) crystal surface of the physically mixed sample can be observed, 43 and a similar shift is observed at 7.71°. According to Bragg's law: 44 2 d sin θ = nλ . When nλ is a constant value, the redshift phenomenon represents a decrease in the spacing of the crystalline surfaces, 45 which suggests a change in the band gap of the physical mixture.…”