Microrheology of colloidal dispersions by Brownian dynamics simulations.

@article{2307883520051101, abstract = {We investigate active particle-tracking microrheology in a colloidal dispersion by Brownian dynamics simulations. A probe particle is dragged through the dispersion with an externally imposed force in order to access the nonlinear viscoelastic response of the medium. The probe’s motion is governed by a balance between the external force and the entropic ``reactive'' force of the dispersion resulting from the microstructural deformation. A ``microviscosity'' is defined by appealing to the Stokes drag on the probe and serves as a measure of the viscoelastic response. This microviscosity is a function of the P{\'{e}}clet number (\$Pe=Fa/kT\$) — the ratio of ``driven'' (\$F\$) to diffusive (\$kT/a\$) transport — as well as of the volume fraction of the force-free bath particles making up the colloidal dispersion. At low Pe — in the passive microrheology regime — the microviscosity can be directly related to the long-time self-diffusivity of the probe. As Pe increases, the microviscosity ``force-thins'' until another Newtonian plateau is reached at large Pe. Microviscosities for all P{\'{e}}clet numbers and volume fractions can be collapsed onto a single curve through a simple volume fraction scaling and equate well to predictions from dilute microrheology theory. The microviscosity is shown to compare well with traditional macrorheology results}, author = {Carpen, Ileana C. and Brady, John F. }, citeulike-article-id = {1574461}, journal = {Journal of Rheology}, keywords = {microrheology, simulation, theory}, number = {6}, posted-at = {2007-08-19 00:34:44}, priority = {2}, title = {Microrheology of colloidal dispersions by Brownian dynamics simulations.}, url = {http://search.ebscohost.com/login.aspx?direct=true\&\#38;db=a9h\&\#38;AN=23078835\&\#38;site=ehost-live}, volume = {49}, year = {20051101} }

TY - JOUR ID - 2307883520051101 L3 - citeulike-article-id:1574461 TI - Microrheology of colloidal dispersions by Brownian dynamics simulations. JF - Journal of Rheology VL - 49 IS - 6 N2 - We investigate active particle-tracking microrheology in a colloidal dispersion by Brownian dynamics simulations. A probe particle is dragged through the dispersion with an externally imposed force in order to access the nonlinear viscoelastic response of the medium. The probe’s motion is governed by a balance between the external force and the entropic ``reactive'' force of the dispersion resulting from the microstructural deformation. A ``microviscosity'' is defined by appealing to the Stokes drag on the probe and serves as a measure of the viscoelastic response. This microviscosity is a function of the P{\'{e}}clet number ($Pe=Fa/kT$) — the ratio of ``driven'' ($F$) to diffusive ($kT/a$) transport — as well as of the volume fraction of the force-free bath particles making up the colloidal dispersion. At low Pe — in the passive microrheology regime — the microviscosity can be directly related to the long-time self-diffusivity of the probe. As Pe increases, the microviscosity ``force-thins'' until another Newtonian plateau is reached at large Pe. Microviscosities for all P{\'{e}}clet numbers and volume fractions can be collapsed onto a single curve through a simple volume fraction scaling and equate well to predictions from dilute microrheology theory. The microviscosity is shown to compare well with traditional macrorheology results KW - microrheology KW - simulation KW - theory AU - Carpen, Ileana AU - Brady, John PY - 20051101/// UR - http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=23078835&site=ehost-live ER -