Percolation approach to proton conductivity in hydrated protein powders

Abstract

The dielectric response of hydrated myoglobin powder has been measured in the range 10⁶-10⁹Hz. The data reveal at least two distinct processes which are explained by reorientation of water dipoles and conduction of protons along connected patches of water molecules. It is shown that proton hopping may be approximated by a simple percolation model, which predicts an algebraic low-frequency divergence ε(Ω)αΩ^−0.5 at the threshold.