Hybrid cellulose nanofibril/MXene/polydimethylsiloxane conductive composites for enhanced strain sensing

Abstract Fabrication of stretchable hybrid cellulose nanofibril (CNF)/MXene/polydimethylsiloxane (PDMS) nanocomposite sensors is a challenging task due to inherent incompatibility between hydrophilic CNFs and MXene, and hydrophobic PDMS. In this work, a porous CNF sponge embedded with MXene nanoflakes was created, which was then infiltrated with PDMS to form a flexible, stretchable nanocomposite film. The resultant CNF/MXene network within the PDMS matrix enhanced electrical conductivity and strain sensitivity, while the PDMS provided mechanical flexibility. Scanning and transmission electron microscopy images revealed a well-integrated structure with good dispersion of MXene along CNFs, promoting strong interfacial interactions and mechanical stability. The sensor demonstrated consistent mechanical performance, with tensile strengths of 320 ± 19 kPa and 400 ± 24 kPa at 5% and 10% strains, respectively. Strain sensing tests revealed ΔR/R0 increased in the 0–17% strain range, with a higher gauge factor at increased strain levels, making it suitable for small workable strain ranges. Furthermore, thermal analysis showed that the incorporation of MXene accelerated thermal degradation, while the addition of PDMS enhanced the thermal stability of the composite, resulting in improved durability for long-term strain sensing applications. Graphical abstract