Electronic conduction in water-adsorbed kenaf cellulose.

Kenaf cellulose can absorb a considerable amount of water, up to approximately 17.5 wt% of its dry weight at saturation. As the water content increases, the imaginary part of the impedance increases, and dielectric loss in the parallel circuit decreases. Direct current conduction, which exhibits ohmic behaviour at low water concentrations, shows rectification in sample with 6% or more water. This behaviour is attributable to radical electrons, as observed in the electron spin resonance spectra of samples containing water. These phenomena suggest that water exists as a solid rather than a fluid in cellulose. First-principles calculations predict that at saturated water levels, water is fixed as a single molecular quasi-solid layer on the hydrophilic surfaces surrounding the nanofibrils. Consequently, water-adsorbed cellulose can be considered as a solid electronic conductor.