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 …