Viscosity of Collagen Solutions: Influence of Concentration, Temperature, Adsorption, and Role of Intermolecular Interactions

An investigation of the influences of the adsorption, electrolyte, shear rate, and temperature on the viscometric behavior of collagen solutions was performed using a photoelectric viscometer. The experimental results showed an abnormal behavior of the reduced viscosity (eta(sp)/C) of dilute collagen solutions measured by a viscometer with or without a hydrophobic surface treatment; the reduced viscosity increased with decreasing concentration. This phenomenon can be completely eliminated by increasing the concentration of an added salt. It indicated that the abnormal viscosity resulted from a long-ranged, inter-molecular electrostatic force. The reduced viscosity decreased as the shear rate increased. The shear-thinning cavitation phenomenon resulted from the high aspect ratio of the collagen molecules. The reduced viscosity of the collagen solutions increased with an increase in temperature, which was due to the association of collagen molecules at high temperature.