Tough, Self-Healing, and Antimicrobial Hydrogel Sensors Based on Hydrogen-Bonded, Cross-linked Chitosan and MWCNTs

Conductive hydrogels, as a flexible electronic material,have foundemerging applications in the fields of wearable devices, health monitoring,and electronic skin. However, the current conductive hydrogels lackantimicrobial properties and excellent mechanical properties, whichseverely limit their applications in wearable and biological interfaces.Herein, a conductive nanocomposite hydrogel consisting of silver nanowires(AgNWs), carboxylated carbon nanotubes (c-MWCNTs), chitosan (CS),and polyacrylamide (pAAm) was prepared by in situ free-radical polymerizationwithout adding any cross-linking agents. Ingeniously, physical interactions(hydrogen bonding) endow the hydrogels with excellent tensile strength(503.64 kPa), ultrahigh tensile (16,000%), high toughness (22.8 MJ & BULL;m(-3)), and self-healing properties. Remarkably, hydrogelsbased on AgNWs and CS exhibit excellent antibacterial activity against Staphylococcus aureus, Escherichiacoli, and Bacillus subtilis. Simultaneously, under the synergistic effect of AgNWs and c-MWCNTs,the fabricated conductive hydrogel sensor exhibits excellent strainsensitivity (gauge factor = 10.42, up to 900%), high conductivity,and fast response time (200 ms). The c-MWCNTs-AgNWs-based hydrogelsensors can sensitively and stably detect human activities, whichshow that pAAm/c-MWCNTs@CS-AgNWs hydrogels have great potential inthe fields of human activity monitoring, e-skin, and soft electronicdevices.

Automated summary

A conductive nanocomposite hydrogel with antimicrobial properties and excellent mechanical properties was successfully prepared, which has great potential in the fields of wearable devices, health monitoring, and electronic skin.