Conductive hydrogels are promising interface materials utilized in bioelectronics for human-machine interactions. However, the low-temperature induced freezing problem and water evaporation-induced structural failures have significantly hindered their practical applications. To address these problems, herein, an elaborately designed nanocomposite organohydrogel is fabricated by introducing highly conductive MXene nanosheets into a tannic acid-decorated cellulose nanofibrils/polyacrylamide hybrid gel network infiltrated with glycerol (Gly)/water binary solvent. Owing to the introduction of Gly, the as-prepared organohydrogel demonstrates an outstanding flexibility and electrical conductivity under a wide temperature spectrum (from −36 to 60 °C), and exhibits long-term stability in an open environment (>7 days). Additionally, the dynamic catechol-borate ester bonds, along with the readily formed hydrogen bonds between the water and Gly molecules, further endow the organohydrogel with excellent stretchability (≈1500% strain), high tissue adhesiveness, and self-healing properties. The favorable environmental stability and broad working strain range (≈500% strain); together with high sensitivity (gauge factor of 8.21) make this organohydrogel a promising candidate for both large and subtle motion monitoring.
The
ionic conducting hydrogel has attracted tremendous attention
in fabricating flexible artificial skin-like devices. However, there
are still unsolved challenges in hydrogel-based ionic skins, such
as poor fulfillment of stretchability and compliance and weak interface
interaction, as well as single sensory function. Herein, a high-performance
organohydrogel-based ionic skin is facilely fabricated through one-step
UV-initiated polymerization, in the presence of a polyacrylamide/cellulose
nanofibril (PAAm/CNF) hybrid skeleton, a tannic acid (TA)-functionalized
interface, and electrolytes (NaCl) dissolved in a glycerol–water
binary solvent network. The design strategy demonstrates a profound
synergistic effect of interpenetrating networks and interbonding structure
in improving ultrastretchability (up to 1430%), suitable Young’s
modulus (≈23 kPa), and high ionic conductivity (2.7 S m–1). Inspired by the adhesive mechanism of catechol
groups in the mussel foot proteins, the TA component provides a durable
interfacial contact (self-adhesiveness ≈ 103 N m–1) and unexpected UV-blocking capability (efficiency >99.9%). Moreover,
by introducing a glycerol/water solvent system, the organohydrogel
achieves desirable environmental stability. Furthermore, benefiting
from the superior mechanical response and thermal perception capacities,
our ionic skin can be assembled as capacitance sensors for real-life
motion monitoring as well as thermistors for dynamic temperature detection.
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