Description:
<jats:title>Abstract</jats:title><jats:p>The properties of polyvinylpyrrolidone, in water and salt solutions, are examined by measuring the heat capacities, specific volumes and reduced viscosities. The heats of solution in water are of the order of −4 kcal per mole of monomer unit, they are decreased in the presence of salts. The results are discussed in terms of the mechanism of the stabilizing effect of hydrophylic colloids on hydrophobic ones. No evidence is found in terms of the existence of more “structural water” in the vicinities of the polymer molecules; this is taken to imply that stabilization is not effected through hydration multilayers of “ice‐like water”. A mechanism of stabilization based on the signs and magnitudes of the heats of solution of colloids in water is proposed.</jats:p>