Shear-induced dimerization

The Yamada-Kawasaki theory of nonlinear response was applied to the calculation of the frequency and shear-rate dependent shear viscosity of a dilute Brownian suspension of harmonically bound dumbbells. When the dumbbells were allowed to dimerize, as implemented by the Wertheim theory of association, the resulting fluid displayed exhibited shear-thinning and shear-thickening regimes. Head-to-head dimerization led to shear thinning, and for shear thickening to occur, the rotational correlation time of the dimers must be commensurate with those of the monomers, The present findings were evaluated in light of the observed shear-induced coagulation in micellar solutions. (C) 1997 American Institute of Physics.