Surface rheological properties of hyaluronic acid solutions

Using an oscillating ring surface rheometer, surface shear rheological studies of hyaluronic acid solutions at physiological pH have demonstrated the elastico-viscous nature of the surface films. The properties of these surface films change with time and are shown to be related to bulk concentration, ionic strength and pH. This ageing behaviour can be explained on the basis of molecular conformational changes and molecular segmental kinetics. The results are discussed in relation to the postulated function of hyaluronic acid in synovial fluid.