Non-newtonian surface viscosity

Abstract

The results of surface rheology are explained and quantitatively described by the help of a simple molecular model of the flow behaviors in monolayers. The fundamental processes of this rheological pattern are: 1. 1. The transport of substrate water molecules rigidly bound to the molecules of the flowing monolayers. 2. 2. The deformation by the flow of the quasi-lattice structure of the film, the relaxation velocity of which determines the type of behavior, Newtonian or not, in relation to the respective values of the rate of shear and of the interaction energies between the kinetic units. 3. 3. The microscopic or macroscopic phase changes induced in the monolayer by the flow and causing, for instance, the shear hardening phenomenon, the various time effects, and the decrease of the apparent molecular area. The three types of processes are correlative and simultaneous. As a consequence of the reciprocal interaction between structure and rate of shear, the actual flow behavior of a monolayer depends upon its total rheological history.