Business - Colloquium
Monday, February 12, 2007
4:00 PM-5:00 PM
Olin Hall
107
Suspensions of colloidal particles are astounding model systems used
to study a variety of fundamentally important problems in soft matter
physics. The versatility of colloids is due in large part to the
increasing sophistication of their synthesis, and the relative
simplicity of their interactions. This talk will discuss recent
experimental results on two soft-matter topics that utilize colloidal
particles; clogging during flow and jamming in glasses.
I will first present results from microfluidic studies of clogging in
model porous media. By using simple imaging techniques, and a minimal
geometric model, I will describe the physical origins of clogging in
microfluidic devices. These results demonstrate that the aggregation
of micron sized particles, in a low Reynolds number flow, is dominated
by single particle interactions. In the second half of the talk, I
will discuss the microscopic response of colloidal glasses to a
macroscopically applied compressive stress. Using time resolved laser
scanning confocal microscopy, I identify and track the motion of
thousands of colloidal particles in real space over very long times.
With this technique, and ideas garnered from metallic glasses, the
complete local strain tensor for each particle is determined. I will
demonstrate that highly localized, correlated shear and compression
transformations are necessary for colloidal glasses to approach a
maximally jammed state.
Cost: FREE
Sponsored by: WPI Physics Department, Dr. Stephen Jasperson
Suggested Audiences: College
E-mail:
snj@wpi.edu
Phone: 508-831-5322
Last Modified: February 2, 2007 at 8:29 AM
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