CONDUCTION AND ELECTROLYSIS IN CELLULOSE

Abstract

Dry cellulose conducts in accordance with the theoretical expression for the temperature dependence of ionic conductivity. The appearance of products of electrolysis in approximate agreement with Faraday's law and the presence of gaseous hydrogen as the main component indicate that the conduction is ionic (rather than electronic, as in organic semiconductors), and that it depends upon the migration of protons and proton holes. It is proposed that conduction in dry cellulose involves tunneling of the proton between equivalent sites, the one in the ion, the other in an adjacent neutral molecule. Resonance tunneling occurs when these structures are in suitable mutual configurations. This occurs with a frequency given by a Boltzmann factor. Experiment indicates that the energy in this factor is 10.6 kcal/mole. As this is about twice the energy of the hydrogen bond, it is proposed that the energy of activation for mobility represents the simultaneous breaking of two hydrogen bonds in bringing adjacent structures into suitable configuration for resonance tunneling. The results are considered to exhibit an example of an organic dielectric which conducts by the transport of protons at a rate depending upon an activation energy due to the breaking of hydrogen bonds.A small dependence of the molar yield of gas per Faraday on the applied voltage gradient was observed. Its significance is discussed in terms of a generalization of the electrode process to include effects of field emission as the voltage gradient approaches the breakdown level.