Electrical conduction of cellulose under DC field

Abstract

The temperature gradient of crystal lattice spacings and X-ray reflection intensities has been found to change discontinuously at 150 degrees C for cellulose I (Cell I) and at 100 degrees C for cellulose II (Cell II). These breaks reflect a transition related to the onset of the backbone motion in the crystalline phase. The authors have attempted to confirm this conclusion by measuring the DC conductivity from room temperature to about 230 degrees C for Cell I and Cell II both parallel and perpendicular to the fiber direction. The conduction mechanism is discussed in relation to the absorption current of Cell I under a DC field in the temperature range from 140 degrees C to 230 degrees C, where the DC conductivity becomes relatively high. The results indicate that the increase of carrier mobility above the transition temperature of crystallites arises from the backbone motion in the disordered crystalline phase (mesophase) and that proton transfer is an elementary mechanism for both absorption and steady currents.<>