Shear Wave Propagation in a Birefringent Viscoelastic Medium

Abstract

A theoretical and experimental study is described for the optical birefringence associated with the propagation of a plane shear wave in a viscoelastic medium. The shear wave propagation is characterized by a complex propagation constant from which the complex coefficient of shear viscosity of the medium may be derived. The optical birefringence is related to the mechanical action of the shear wave by a complex mechano-optic coefficient. In the experiment the birefringence due to the shear wave is analyzed by transmitting circularly polarized light through the material at right angles to the direction of shear wave propagation and to the direction of particle displacement. The modified, circularly polarized light is then analyzed by a plane analyzer and a photomultiplier detector. The mechanical and mechano-optic constants for the medium are determined for an aqueous milling yellow solution and for a polystyrene solution and are compared with independent determinations of these same factors from other experiments.

Extensions of the Ferry shear wave model for active linear and nonlinear microrheology

“…The experimental technique and associated modeling and analysis are extensively discussed in the literature [30, 7, 2, 13, 14]. Linear viscoelastic constitutive equations, coupled with momentum balance and boundary conditions, yield an exact solution for a semi-infinite domain.…”

Molecular simulation and continuum mechanics investigation of viscoelastic properties of fluids confined to molecularly thin films

“…The importance of these shear wave propogation effects on the experimental determination of dynamic rheological properties has been pointed out in the literature. [22][23][24][25] Using the theory of waves, Schrag and co-workers [23][24][25] have presented expressions for the velocity and shear rate profiles ͑as functions of time and position͒ in the fluid when these inertial effects play an important role. Here we present a brief outline of an alternate derivation of these expressions starting from the equation of motion of the fluid.…”