R. Drouot

TL;DR: In this paper, a phenomenological-thermodynamical model for the anomalous behavior of the flow of deformable macromolecules is presented, where the structural deformation is characterized by means of a quantity which may be a scalar, a vector or a tensor, and is considered as a so-called internal variable.

TL;DR: In this article, a thermodynamic scheme for polyelectrolyte solutions in an electric field is elaborated and a suitable set of restrictions upon the constitutive assumptions is derived, and a set of constitutive equations so obtained is then specialized in order to set up simple descriptions of particular phenomena.

TL;DR: In this article, it is shown that Tirrell's diffusion flux can be deduced from a macroscopic modelling which involves second-order gradients and a vectorial internal variable related to the microstructure.

Abstract: A phenomenological model for solutions of polyelectrolytes accounting for electromechanical interactions is proposed within the framework of continuum thermodynamics. The modelling involves the conformation of macromolecules in the form of a tensorial “internal variable” and the electric polarization of the solution. The paper aims to demonstrate the possible competition between flow and electricity effects on rigorous phenomenological grounds. Three kinds of dissipative mechanisms are accounted for: viscosity of the solution, electric relaxation and the relaxation of the conformation of macromolecules. Anisotropic effects induced by the applied electric field and flow-induced polarization through changes in conformation are exhibited. These effects are small. By way of application, the problem of the orientation and conformation taken by macromolecules of polyelectrolytes under the combined influence of a simple shear flow and a longitudinal or orthogonal electric bias field is treated in detail and illustrated graphically. Some optical properties are mentioned.

TL;DR: In this paper, a thermodynamic phenomenological approach to complex fluids is presented in which the underlying microstructure is accounted for through a so-called internal variable of state, which may diffuse.