Effect of adsorption on the viscosity of dilute polymer solution

Measurements of the dilute solution viscosities of polyethylene glycol and polyvinyl alcohol in water were carried out. The reduced viscosities of both polymer solutions show an upward turning of curvature at the extremely dilute concentration region and this is similar to the phenomena observed for many polymer solutions in the early 1950s. Upon the changes of the flow lime of pure water and the wall surface wettability of the viscometer after measuring solution viscosity, a judgement was formed that the observed viscosity abnormality at the extremely dilute concentration region is solely due to the effect of adsorption of polymer chains on the viscometer wall surface. A theory of the adsorption effect based on the Langmuir isotherms was proposed and a mathematical analysis for data treatment was performed. The theory could adequately describe the existing viscosity data. It seems necessary to correct the viscosity of a dilute polymer solution measured by a glass capillary viscometer for effect of adsorption in all cases. (C) 1998 Elsevier Science Ltd. All rights reserved.