Chestnut-Tannin-Crosslinked,
Antibacterial, Antifreezing,
Conductive Organohydrogel as a Strain Sensor for Motion Monitoring,
Flexible Keyboards, and Velocity Monitoring
posted on 2022-12-23, 13:07authored byBin Song, Xin Fan, Haibin Gu
Flexible sensing devices (FSDs) fabricated using conductive
hydrogels
have attracted researchers’ extensive enthusiasm in recent
years due to their versatility. Considering the complexity of their
application environments, the integration of various functional characteristics
(e.g., excellent mechanical, antibacterial, and antifreezing properties)
is an important guarantee for FSDs to stably perform their applications
in different environments. Herein, we developed a multifunctional
conductive polyvinyl alcohol (PVA) organohydrogel PVA-CT-Ag-Al-Gly
(PCAAG) by using a green, natural, and cheap biomass, chestnut tannin
(CT), as a crosslinking agent, nano-silver particles (AgNPs) as an
antimicrobial agent, aluminum trichloride (AlCl3) as a
conducting medium, and the mixed water–glycerol as the solvent
system. In this organohydrogel system, CT acted not only as the reducing
and stabilizing agent for the preparation of antibacterial AgNPs but
also as the crosslinking agent owing to its strong multiple hydrogen
bonding interactions with PVA, realizing its multifunctional application.
The PCAAG organohydrogel possessed outstanding physical and mechanical
properties (350.54% of the maximum fracture strain and 1.55 MPa of
the maximum tensile strength), considerable bacteriostatic effects
against both Escherichia coli and Staphylococcus aureus, and excellent freeze resistance
(it could function normally at −20 °C). The motion-monitoring
sensor based on the PCAAG organohydrogel exhibited excellent specificity
recognition for both large-amplitude (e.g., elbow bending, wrist bending,
finger bending, running and walking, etc.) and small-amplitude (frowning
and swallowing) human movements. The flexible keyboard constructed
by using the PCAAG organohydrogel could easily achieve the transformation
between digital signals and electrical signals, and the signal output
had both specificity and stability. The velocity-monitoring sensor
fabricated by using the PCAAG organohydrogel could accurately measure
the speed of the object movement (less than 3% of relative error).
In short, the present PCAAG organohydrogel solves the problems of
the single application environment and a few application scenarios
of traditional conductive hydrogels and possesses remarkable application
potential as a multifunctional FSD in many fields such as artificial
intelligence, sport management, soft robots, and human–computer
interface.