A new strategy to improve the dielectric properties of cellulose nanocrystals (CNCs): Surface modification of small molecules

Nanocellulose finds various applications in advanced electrical devices due to its impressive mechanical properties, thermal stability , and degradability. Cellulose nanocrystals (CNCs) with excellent dielectric properties may act as a fresh dielectric plastic. In this study, a new strategy of small molecule modification was used to improve the dielectric constant , breakdown strength, and band gap of the CNCs. The dipole moments , dipole density, and the anisotropic impact of surface groups on the dielectric constant were studied. The number of sulfates in the CNCs showed a gradient due to alkali treatment and sulfonation , which allowed for a controlled range of the dielectric constant of nanocellulose between 4.9 and 11.9. TEMPO oxidation (2,2,6,6-tetramethylpiperidine-1-oxyl) and cyanoethylation of the CNCs further increased the dielectric constant to 11.1 and 13.2, respectively, and the dielectric loss 10 −1 . By understanding and innovating organic polymer dielectrics, we can provide significant benefits to the electronics and device industries.