Enthalpy of Mixing Glycosaminoglycans with Aqueous NaCl

Calorimetric measurements of Δ H , the enthalpy of mixing with NaCl solutions per mole of polymer charge equivalent, have been made for the sodium salts of hyaluronate, chondroitin 4‐sulfate, and chondroitin over the range m s f = 0–0.5 (where m s f is final NaCl molality); corrections were made for the enthalpy of dilution of NaCl. Values of Δ H for the range m s f = 0–0.1 agree reasonably well with a theoretical estimate from the infinite line charge theory of polyelectrolytes. In order to apply the latter, calculations of several average short‐range atomic spacings in hyaluronate were made from a statistical model with use of energy parameters which provide a good fit to experimental values of unperturbed dimensions.