Laser tweezer microrheology of a colloidal suspension

@article{citeulike:2730851, abstract = {The microrheology of a colloidal suspension is measured using laser tweezers. Suspensions of refractive index-matched fluorinated ethylene propylene (FEP) particles are seeded with index-mismatched polystyrene or silica probe particles. Laser trapped probes are then subjected to steady uniform flows, enabling measurements of the suspension microviscosity as a function of FEP volume fraction and flow velocity. The microrheology results agree with bulk rheology, and both exhibit the same volume fraction dependence of the Krieger-Dougherty relationship for hard spheres. As volume fraction increases, the microrheology more closely agrees with the infinite shear bulk viscosity. In this regime, measurements using small probes exhibit additional shear thinning. Using confocal microscopy and fluorescent poly(methylmethacrylate) dispersions, we demonstrate that the nonlinear microrheology is consistent with the development of an anisotropic nonequilibrium pair distribution function between the probe and bath particles, with a denser region at the leading surface of the probe and a wake trailing it. The nonlinear response and underlying microstructure are in qualitative agreement with recent theory [T. M. Squires and J. F. Brady, Phys. Fluids 17, 073101 (2005)]. \©2006 The Society of Rheology}, author = {Meyer, Alexander and Marshall, Andrew and Bush, Brian G. and Furst, Eric M. }, citeulike-article-id = {2730851}, doi = {10.1122/1.2139098}, journal = {Journal of Rheology}, keywords = {colloids, microrheology, opticaltweezer, technique}, number = {1}, pages = {77--92}, posted-at = {2008-04-28 20:24:09}, priority = {2}, publisher = {SOR}, title = {Laser tweezer microrheology of a colloidal suspension}, url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal\&id=JORHD2000050000001000077000001\&idtype=cvips\&gifs=yes}, volume = {50}, year = {2006} }

TY - JOUR ID - citeulike:2730851 TI - Laser tweezer microrheology of a colloidal suspension JF - Journal of Rheology VL - 50 IS - 1 SP - 77 EP - 92 PB - SOR N2 - The microrheology of a colloidal suspension is measured using laser tweezers. Suspensions of refractive index-matched fluorinated ethylene propylene (FEP) particles are seeded with index-mismatched polystyrene or silica probe particles. Laser trapped probes are then subjected to steady uniform flows, enabling measurements of the suspension microviscosity as a function of FEP volume fraction and flow velocity. The microrheology results agree with bulk rheology, and both exhibit the same volume fraction dependence of the Krieger-Dougherty relationship for hard spheres. As volume fraction increases, the microrheology more closely agrees with the infinite shear bulk viscosity. In this regime, measurements using small probes exhibit additional shear thinning. Using confocal microscopy and fluorescent poly(methylmethacrylate) dispersions, we demonstrate that the nonlinear microrheology is consistent with the development of an anisotropic nonequilibrium pair distribution function between the probe and bath particles, with a denser region at the leading surface of the probe and a wake trailing it. The nonlinear response and underlying microstructure are in qualitative agreement with recent theory [T. M. Squires and J. F. Brady, Phys. Fluids 17, 073101 (2005)]. ©2006 The Society of Rheology KW - colloids KW - microrheology KW - opticaltweezer KW - technique AU - Meyer, Alexander AU - Marshall, Andrew AU - Bush, Brian AU - Furst, Eric PY - 2006/// UR - http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JORHD2000050000001000077000001&idtype=cvips&gifs=yes ER -