Cryopolymerized Polyampholyte Gel with Antidehydration, Self-Healing, and Shape-Memory Properties for Sustainable and Tunable Sensing Electronics

Abstract

Hydrogel-based wearable flexible electronics are attracting tremendous interest for use in human healthcare. However, many of the existing hydrogel electronics are often susceptible to dehydration, leading to weakened stretchability and inaccurate signal extraction. Besides, hydrogels are desired to be much smarter for self-repairing physical damage and enabling performance manipulation. Herein, we develop a kind of cryopolymerized polyampholyte gels with the multifunctionality of antidehydration, self-healing, and shape-memory for wearable sensing electronics. The antidehydration property is enabled by the incorporation of glycerol, endowing the sensing electronics with excellent stretchability and strain-sensing performance in long-term monitoring. The ionic bonds in the polyampholyte gel possess a dynamic feature regulated by alternant NaCl­(aq) and H2O treatments, laying the foundation for self-healing and shape-memory. As a result, the sensing electronics can automatically repair physical damages without any sacrifice in sensing performance, after healing both conductivity and strain-sensing performance could return to the initial levels. The shape-memory function enables the temporal adjustment of the initial state of the sensing electronics; both the conductivity and sensing performance, for instance, signal intensity, can be manually manipulated. In all, the cryopolymerized polyampholyte gels with antidehydration, self-healing, and shape-memory properties can be an inspiration to develop sustainable and tunable gel-based electronics for human motion monitoring.

Application of Shape Memory and Self-Healable Polymers/Composites in the Biomedical Field: A Review

“…After healing, conductivity and strain-sensing performance might return to their original levels and can be adjusted temporarily owing to their shape-memory function. Cryopolymerized polyampholyte gels with qualities such as shape memory, self-healing, and antidehydration can inspire the creation of flexible, long-lasting gel-based electronics to monitor human motion . In another work by Xiao et al, shape memory-based self-healable hydrogels were fabricated for wearable strain sensors to increase their longevity and to provide programmable shape control.…”

Polyampholyte Polymers‐Based Sensors: A Review on Stimuli and Applications

“…Overall, the multifunctional properties of PAH make it a promising material for physical monitoring, and it has the potential to revolutionize several industries. [102,103] In order to improve the mechanical characteristics and functioning of their novel form of polyampholyte (PA) hydrogel, Huang et al combined ionic and metal-ligand interactions. They initially produced PA gels by copolymerizing cationic 2-dimethylaminoethyl acrylate with anionic sodium p-styrenesulfonate (NaSS) in order to form these hydrogels (DMAEA-Q).…”

“…The testing was conducted by setting the strain at 150%. Reproduced with permission [102]. Copyright 2022, American Chemical Society.…”

An Autofluorescent Hydrogel with Water‐Dependent Emission for Dehydration‐Visualizable Smart Wearable Electronics

“…Although several strategies have been developed to improve the water retention capacity of hydrogel‐based WFEs, for example, introducing glycerol or lithium chloride (LiCl) as a moisturizing agent, [ 24 ] a remaining issue here is that these strategies only retard the dehydration process as the evaporation of water is spontaneous. Therefore, visualizing the change in the water retention rate in a long‐term application is still vital for estimating the desiccation status in advance and for preventing signal distortion; but unfortunately, this task remains a challenge.…”