Title:
Collapsing Colloidal Gels: How and When?
Collapsing Colloidal Gels: How and When?
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Author(s)
Russel, William B.
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Abstract
Drying colloidal dispersions by evaporating the liquid to create particulate solids, porous
coatings, or continuous films is common to a number of important technologies, ranging
from applying latex paint and manufacturing photographic film to depositing highly porous
coatings on ink jet papers and fabricating photonic crystals from silica sols. The objective is
generally to create a layer of specified thickness and controlled porosity with permeability,
strength, transparency, or other physical properties. Both the understanding and
implementation of drying processes have advanced considerably in the past two decades.
Yet processing still raises a number of interesting and difficult issues because of conflicting
constraints and performance properties. The focus of this talk is the complex phenomena
that emerge as evaporation drives fluid flow in the thin film. Rapid evaporation can
segregate binary mixtures or create an impermeable skin at the surface. Slower evaporation
produces a porous packing subject to a rising capillary pressure that deforms the particles.
Elastic deformation can cause cracking and peeling, while a viscous response can produce a
pore-free solid.
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Date Issued
2012-03-15
Extent
50:44 minutes
Resource Type
Moving Image
Resource Subtype
Lecture