Some Asymmetry Properties of Composite Membranes
Composite membranes of two types, layer-type and sandwich-type, have been prepared from 2% collodion solutions containing different amounts of polystyrene sulfonic acid. The layer-type membranes were formed by evaporating first a collodion solution containing the least amount of the polyelectrolyte. On top of this collodion solutions containing increasing quantities of the poly-electrolyte were evaporated one after the other. Sandwich-type membranes were formed by trapping some polyelectrolyte between two simple membranes, one containing a small quantity and the other containing a large quantity of the polyelectrolyte.
Electrical potentials arising across these membranes when they separate the same concentration of (1:1) electrolyte have been measured as a function of concentration. Long term equilibration of these membranes with very dilute electrolyte solutions tend to lower the potentials observed in the first few hours of equilibration. These results are discussed in terms of a model system built from two simple membrane cells, one containing membrane of high charge density and the other containing membrane of low charge density, in such a way that one membrane cell opposed the emf of the other membrane cell.
KeywordsComposite Membrane Transport Number Giant Axon High Charge Density Membrane Cell
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