Effect of adsorption on the viscosity of dilute polymer solution

Careful measurements of the dilute solution viscosities of polyethylene gly col and polyvinyl alcohol in water were carried out. The reduced viscositie s of both polymer solutions plot upward curves at extremely dilute concentr ation levels similar to the phenomena observed for many polymer solutions i n the early 1950's. Upon observation of the changes of the flow times of pu re water in and the wall surface wettability of the viscometer after measur ing solution viscosity, a view was formed that the observed viscosity abnor mality at extremely dilute concentration regions is solely due to the effec t of adsorption of polymer chains onto the wall surface of viscometer. A th eory of 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 cor rect the viscosity result of dilute polymer solutions measured by glass cap illary viscometer by taking into account the effect of adsorption in all ca ses.