Electrical Conductivity of Hydrogen-Bonded Polymers

Abstract

The d.c. electrical conductivity of poly-γ-benzyl-L-glutamate (PBLG), nylon 66 and calf thymus DNA has been investigated experimentally as the examples of hydrogen-bonded polymers. Energy gaps which are assumed to be the twice of the activation energy are determined by the temperature variation of conductance in the solid dry state; 2.07±0.05 eV for PBLG in α-helix, 2.00±0.05 eV for helical DNA, 4.92±0.05 eV and 1.85±0.05 eV respectively for higher and lower temperature regions of nylon 66 in α-form. The adsorption of polar or nonpolar molecules (H₂O, CH₃OH, C₆H₆) has the effect of increasing the conductivity and decreasing the activation energy of conduction. These results are in disagreement with the values expected from recent theoretical investigations and spectroscopic studies of these samples. Possible conduction mechanisms for these polymers are proposed in the case of solid dry state as well as of the state adsorbing polar or nonpolar molecules.