Multifunctional Ternary Hybrid Hydrogel Sensor Prepared via the Synergistic Stabilization Effect

Abstract

Since highly stretchable hydrogels have demonstrated their promising applications in flexible tactile sensors and wearable devices, the current challenge has been imposed on stretchable and multifunctional electronics. Here, we report a multifunctional sensor composed of a liquid metal (LM) nanodroplet-adhered self-assembled polymeric network, anionic carboxymethylcellulose (CMC), and cationic polyacrylamide (PAAm). The synergistic effect, zeta potential reduction, by CMC and macromolecules enveloped by LM contributes to the stabilization of the ternary system during preparation and, thus, the homogenization of the products. By engineering and optimizing the ternary hybrid hydrogels, excellent extensibility (tensile strain near 300%), readily reversible hysteresis loops, and accessible deformability (low modulus of 104 Pa) are afforded. The fabricated sensor exhibits a high tensile strain gauge factor of around 0.7 and a high compressive stress sensitivity of up to 0.12 kPa–1, a fast response time below 125 ms, and a high stability and precision in usage. In a series of practical scenarios, the assembled sensor displays distinguished abilities to monitor bodily motions, record electrocardiograms, authenticate handwriting, discern temperature, and infer materials, making them highly promising for multifunctional intelligent soft sensing.

Two-Dimensional and Three-Dimensional Ultrathin Multilayer Hydrogels through Layer-by-Layer Assembly

“…The potential applications of stimuli-responsive hydrogels that can vary their volume in response to guest molecules have attracted interest because of their potential as sensing systems. − The ability to detect amino acids using hydrogels is particularly intriguing because amino acids are essential building blocks for peptides, neurotransmitters, and proteins in biological organisms. − Because amino acids possess both carboxyl and amino groups, they can form strong metal complexes and can be used as excellent chelators. − We utilized the ability of (PMAA) n multilayer hydrogels to load Cu 2+ ions to explore the stability of the [(PMAA) n -Cu 2+ ] complex in the presence of arginine, histidine, serine, glutamine, and threonine . After Cu 2+ loading, the network experienced suppressed swelling at pH >5 because of a strong interaction between the ions and the carboxylic groups of the PMAA, leading to suppressed PMAA ionization.…”

Highly sensitive and self-healing conductive hydrogels fabricated from cationic cellulose nanofiber-dispersed liquid metal for strain sensors

“…Consequently, the LMbased hydrogels obtained show limited sensitivity (gauge factor, GF). Using hydrophilic polymers such as polyvinyl alcohol (PVA) [38], tannic acid-crosslinked PVA [39], and epichlorohydrin-crosslinked chitosan quaternary ammonium salt [43] to stabilize LM droplets or using carboxymethylcellulose (CMC) [44] to costabilize LM droplets with AM can substantially reduce the sedimentation and coalescence of LM droplets. However, the stretchability of the conductive hydrogels obtained is rather low, probably because of the low flexibility of crosslinked PVA and chitosan quaternary ammonium salt, where they solely constitute the polymeric matrices of the corresponding conductive hydrogels, or because of double network formation with reduced stretchability by stiff CMC and in situ synthesized and crosslinked PAM.…”

Molecule‐Assembled Plasmonic Gold Nanoparticle Network for Piezophototronic and Human Activity Detections

“…With the rapid advancement of intelligent technology, multifunctional flexible sensors are of great interest that functionally meet the demands of robotic interfaces, smart medical prognosis, and flexible electronics. [1][2][3] Physiology inspired devices with nanostructured materials such as metal oxides, [4] polymers, and polymer composites [5] are reported to emulate human tactile sensory and reflex behaviors as purposed by wearable gadgets, primary healthcare platforms, and electronic skin for robotic interfaces. In this regard, the current focus is on the tactile sensors that can perceive external mechanical stimuli such as stress, strain, torsion, spatiotemporal touch patterns, heartbeat, and breathing sequence and translate them into recognizable electrical signals or digital images.…”