Nanocellulose's molecular/granular dual-promotion on carbon nanotubes dispersion for piezo-electric/resistive...

Chemical modification of conductive fillers is commonly employed in hydrogel-based flexible sensors to address poor interfacial compatibility; however, such treatments often compromise electrical conductivity, thereby limiting practical applications. In this work, we propose a nanocellulose-assisted strategy to promote carbon nanotube (CNT) dispersion without chemical modification, driven by increased granular disorder and synergistic molecular secondary interactions. Cellulose nanocrystals (tCNC) are introduced as polarization-active sensing units while simultaneously acting as dispersion promoters. CNT are incorporated to construct a conductive percolation network, enabling efficient electrical signal transmission under external strain and concurrently enhancing tCNC polarization. Polyvinyl alcohol and silk fibroin are employed to form a hydrogen-bonded double-network architecture, significantly improving the mechanical robustness of the hydrogel. Owing to the effective dispersion of CNT induced by tCNC, the hydrogel exhibits a high strain sensitivity, with a gauge factor of 4.08 along the stretching direction. Conversely, CNT incorporation markedly enhances tCNC polarization, increasing the piezoelectric sensitivity to 0.47 while suppressing nonlinear responses. The resulting double-network hydrogel achieves a tensile strength of 555.35 kPa. Furthermore, the hydrogel demonstrates thermoplastic processability and recyclability at 70 °C, reducing electronic waste and offering a sustainable platform for wearable biomedical and intelligent interactive applications.