Adsorption-entanglement layers in flowing high molecular weight polymer solutions II. The effect of the nature of the surface

Adsorption-entanglement layers are thick, i.e. multimolecular, layers formed at solid surfaces from solutions of high molecular weight polymers in a state of flow. This publication, the second part of a series of four, is concerned with the effect that the chemical nature of the surface has on formation of these layers. It is shown that for the solutions of polyethylene (PE) and polymethylmethacrylate (PMMA) the layers form most readily on carbon surfaces. Further it is shown that in the case of PE, addition of aluminium stearate can prevent formation of the layers along steel surfaces.These and other effects reported in the paper all bear on actual situations encountered in rheological practice and in particular on the measurement of viscosities. It is concluded that the marked dependence of layer formation on the chemical nature and treatment of the surface is responsible for the differences in viscosity measurements featuring in earlier works by different authors.