Multifunctional MXene Conductive Zwitterionic Hydrogel for Flexible Wearable Sensors and Arrays

Abstract

Conductive hydrogels have good prospects in the fields of flexible electronic devices and artificial intelligence due to their biocompatibility, durability, and functional diversity. However, the process of hydrogel polymerization is time-consuming and energy-consuming, and freezing at zero temperature is inevitable, which seriously hinders its applications and working life. Herein, zwitterionic conductive hydrogels with self-adhesive and antifreeze properties were prepared in one minute by introducing twodimensional (2D) MXene nanosheets into the autocatalytically enhanced system composed of tannic acid-modified cellulose nanofibers and zinc chloride. The system has strong environmental applicability (−60 to 40 °C), good stretchability (ductility ≈ 980%), durable adhesion (even after 30 days of exposure to air), and strong electrical conductivity (20 °C, 30 mS cm −1 ). By virtue of these advantages, the prepared zwitterionic hydrogels can be developed into flexible strain sensors to monitor large human movements and subtle physiological signals over a wide temperature range and to capture signals from handwriting and voice recognition. In addition, multiple flexible sensors can be assembled into a three-dimensional (3D) array, which can detect the magnitude and spatial distribution of strain or force. These results demonstrate that the prepared zwitterionic hydrogels have promising applications in the fields of medical monitoring and artificial intelligence.

Multifunctional Conductive Double-Network Hydrogel Sensors for Multiscale Motion Detection and Temperature Monitoring

“…For glass sheets, the adhesion is primarily derived from the ion-dipole interaction between negatively charged silicate and amine groups of the hydrogel. Hydrogen bonds and hydrophobic interaction are the main factors for the adhesion of hydrogel to rubber and plastic, while metal coordination facilitates the interfacial interaction between metal and hydrogel. ,− The adhesion strength on pig skin can reach 12 kPa, which indicates that the SBG hydrogel can adhere well to human skin tissue. Importantly, the hydrogel can be peeled off from the pig skin without a residue (Movie S1).…”

Conductive nanocomposite hydrogels for flexible wearable sensors

“…In the case of ion-conductive hydrogels, the directional transport of free ions determines their electrical conductivity. 51 However, ion-conducting hydrogels usually require a high salt concentration to achieve electrical conductivity, which is not friendly to the biocompatibility of composite hydrogels. Thus, to further enhance the biocompatibility and electrical conductivity of ionic hydrogels, introducing highly ordered nanostructures as ion transport channels in polymer matrices is an effective way to prepare hydrogels with excellent properties.…”

Ionic hydrogels-based triboelectric nanogenerators for self-powered human–machine interfaces

“…Benefitting from their biocompatible nature, MXene-based hydrogels can be utilized in tissue engineering, cell culture, drug delivery, and other medical applications [139]. In general, these advantages position MXene as a promising synthetic material for ionic hydrogels in fields like energy, environment, biomedical science, and electronic devices [140,141]. Wang et al [70] developed a MXene-based TENG for constructing self-powered sensing systems to monitor marine environments.…”