Studies on the physical state of water in living cells and model systems. III. The high osmotic activities of aqueous solutions of gelatin, polyvinylpyrrolidone and poly (ethylene oxide) and their relation to the reduced solubility for NA+, sugars, and free amino acids.

Very high osmotic activities of concentrated aqueous solutions of gelatin, polyvinylpyrrolidone, and poly(ethylene oxide) were recorded. These observed values are far above those predictable from the molar concentrations of these polymers or those of aqueous solutions of native hemoglobin of equal concentrations. It was shown that these high osmotic activities are closely associated with the ability of the gelatin- or polymer-dominated water to exclude Na+ salts, sucrose, and glycine. Both phenomena are interpreted as reflecting the polarization of multilayers of water by the polymers enhancing the H2O to H2O interaction and also reducing the translational and rotational motional freedom of the water.