Suspensions of densely packed colloidal particles are a
simple model system which exhibits a glass transition, as the
concentration of the particles is increased. We use confocal
microscopy to look at the particles and determine how their
motion changes as the glass transition occurs. We study these
materials in situations including flow through tubes and being
poked with tiny magnetic beads. These experiments give us
insights into the glass transition in a fashion impossible
for regular glasses.
We also study the properties of other complex materials, including foams and sand. See below for information about our various projects. |
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![]() Diffusing rods We look at the Brownian motion of rods tumbling and drifting in 3D. What does their motion tell us about the viscoelastic properties of their medium? |
![]() Confinement and the glass transition The glass transition is modified in confined spaces, but it's unclear why. We're studying colloidal particles confined between two parallel walls; we find their motion slows down. |
![]() Aging of colloidal glasses |
![]() Microrheology of interfaces |
![]() Emulsion glasses We visualize how droplets deform in a concentrated emulsion. In some circumstances emulsions can act like a glass, and studying the deformed droplet shapes should help us understand the emulsion glass transition. |
![]() Poking colloids with magnets We put small magnetic beads into colloidal glasses and pull on them with really strong neodymium magnets. How does this disturb the particles? |
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![]() | Random close packing in confinement: How tightly can you pack a mixture of small and large spheres into a container? And how does the answer change when the container is not much larger than the spheres themselves? |
![]() | Tetrahedral structure in aging colloids: As colloidal glasses age, does their structure change? We find not, but that the local structure is correlated with the dynamics of the particles. |
![]() | Microscopic behavior of flowing colloids: We studied the behavior of colloids as they flow through tiny tubes. As they flow faster, the apparent viscosity decreases. What is the microscopic behavior responsible for this? |
![]() | Structure of colloidal gels: We studied the structure and dynamics of colloidal gels. How does the gel change when we vary the stickiness of the particles? |
![]() | Draining water from foam: As water flows between bubbles in a foam, does it flow like regular flow through a pipe? We found that it depends on the type of soap used to make the foam. Work done in collaboration with Stephan Koehler. |
FUNDING:
Any opinions, findings, and conclusions or recommendations
expressed in this website are those of the author(s) and do not
necessarily reflect the views of the National Science Foundation.
Nor anybody else's views, for that matter, just us. Contact Eric
Weeks at erweeks(at)emory.edu.