Enhancement of Piezoelectricity and Mechanical Properties in Cellulose-Based Elastomers Via Slide-Ring Polyrotaxane Crosslinkers

Cellulose, a bio-based material with high crystallinity, has great potential in the field of piezoelectricity. However, its low processability and poor mechanical robustness limit its use as an additive such as nanoparticles and nanofibers. In this study, a mechanically robust, cellulose-based piezoelectric elastomer with enhanced piezoelectric performance was developed by crosslinking cellulose with polyrotaxane (PR). The effects of cross-linking on the mechanical properties and crystalline structures of the resulting elastomers were investigated. By incorporating slidable polyrotaxane into the cellulose network (eHPC₂₅PR₇₅, 20.4 MJ m^–3), the mechanical toughness increased by up to 2.7 times compared to the pure cellulose network (eHPC₁₀₀, 7.57 MJ m^–3). In addition, the ferroelectric and piezoelectric properties were evaluated from their polarization hysteresis loops and voltage generation characteristics, with eHPC₂₅PR₇₅ showing a power density 4.2 times higher (1.34 μW cm⁻²) than eHPC100 (0.321 μW cm⁻²). The crystallinity and crystalline structure of the fabricated elastomers were analyzed using X-ray Diffraction (XRD), Small Angle X-ray Scattering (SAXS), and Transmission Electron Microscopy (TEM), and their correlation with piezoelectric performance was investigated. Finally, eHPC₂₅PR₇₅ exhibited notable sensitivity to bending and vibrational motions, indicating its potential for use in mechanically robust, flexible piezosensitive devices.