Observations of a new length scale when dense colloidal liquids are poked
Abstract
We use confocal microscopy to directly study the microscopic behavior of dense colloidal liquids at concentrations near the colloidal glass transition. In particular we embed supermagnetic beads in the system of non-magnetic fluorescent PMMA colloids. We exert an external magnetic force on these magnetic beads thus locally perturbing the sample. We investigate the average spatial range of these perturbations as a function of particle concentration and the magnitude of the perturbation. As the glass transition is approached, the spatial extent of the perturbation grows. We also examine the local densities and particle configurations nearby the perturbation, finding that the induced colloidal particle motion is highly spatially heterogeneous.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARL18011W