Aminated Lignin/Cellulose-Based Hydrogel with High Adhesion for Wearable Sensors.

Hydrogels play a significant role in the flexibility, stretchability, and conductivity of wearable sensors. However, it is still a challenge to achieve multifunctional hydrogel sensors with excellent mechanical strength, outstanding self-adhesion, and high stimulus responsiveness for meeting various demands of practical applications. Here, this work presents a one-pot method to prepare a conductive hydrogel with multifunction by introducing aminated lignosulfonate (A-LS) and aminated cellulose nanocrystals (A-CNC) into the hydrogel matrix. Benefiting from the synergistic effect of dynamic reversible noncovalent bond network with the introduction of nanoparticles in the system, the resultant hydrogel showed excellent mechanical properties. In addition, the prepared hydrogels exhibited remarkable adhesion strength (pig skin: 24 kPa) with sustainable adhesion, which still maintained an adhesion strength above 18 kPa after 20 cycles of adhesion/separation. The resultant hydrogel sensor showed a wide operating range (0-200%), high sensitivity (GF = 0.71 at 0-100% strain; GF = 3.15 at 100-200% strain), and fast response time (320 ms). The high-value utilization of renewable forest biomass resources is conducive to the sustainable development of green chemistry.