Abstract
The electric conductance of black lipid membranes in aqueous phases was analyzed on the basis of a protonic conduction scheme by assuming a simple model for the dissociation states of dipolar molecules in the membrane. There appear to be three ways of conduction resulting in this membrane conductance; i.e., the proton conduction via negatively or dipolar charged sites and the hydroxyl ion conduction via positively charged sites. The present scheme of protonic conduction can well explain the conductance behavior of the membranes and it is supported by the fact that the membranes showed potential difference in the theoretical magnitude when subjected to a pH gradient. The potential difference shows, however, anomalous characteristics around pH 5, where the membranes seem to take a composite structure due to the applied pH difference, one-half of the membranes being a proton conductor and the other half a negative hole conductor. The activation energy of the membrane conductance is also discussed in this connection over a wide range of pH.
