Flexible and Transparent PVA/CNF Hydrogel with Ultrahigh Dielectric Constant

High-dielectric-constant poly(vinyl alcohol)/cellulose nanofibril (PVA/CNF) hydrogels were synthesized by a convenience method. An ultrahigh dielectric constant of approximately 4.58 × 109 was obtained for the designed flexible hydrogel at the frequency of 0.1 Hz, and the dielectric loss was also simultaneously about 2.02. The high dielectric constant probably originated from the interfacial polarization arising from the porous and cross-linked structure of the polymer. The abundant hydrogen bonds between PVA and CNFs promote the formation of cross-linked networks. Such materials may break the restrictions on the applications of traditional dielectric materials and expand the usage of dielectric polymers in broad fields.