Title: Applications of mesoscale modeling – towards
computer simulation of cleaning.
Fiona Case
Case Scientific, 125 Main Street, Essex Junction, VT 05453
Fiona@casescientific.com
http://www.casescientific.com/Fiona.html
Abstract:
Liquids that contain mesoscale structures between nanometers (10-9m)
and microns (10-6m) in size are challenging to study, and
yet phenomena that occur at this scale determine the properties
of many scientifically and commercially important materials.
These include personal care products such as liquid hand soap or
shampoo, cosmetics, foods, paints, detergents, the microencapsulation
or delivery systems for drugs, and emulsion polymerization. Mesoscale
behavior is prohibitively expensive to model using atomistic based
simulation techniques (such as molecular mechanics). Yet because of
their sub-micron structure these materials cannot be fully
characterized by their bulk behavior, or modeled using continuum
models. Mesoscale modeling techniques have been developed to study
these types of materials. The most successful is Dissipative Particle
Dynamics (DPD). Starting from a random distribution of model
surfactants, oil and water DPD can predict the formation emulsion
structures as a function of surfactant head and tail size ratio (1).
New work shows that DPD can also predict the formation of oil-in-water
emulsions as surfactants solutions remove oil from a surface. This
suggests that the technique may be able to model key processes in
cleaning.
1) G. Broze, G. and F. H. Case, “Impact of Mesoscale Structure
and Phase Behavior on Rheology and Performance in Superwetting
Cleaners”, Chapter 24 in “Mesoscale Phenomena in Fluid Systems” ACS
Symposium Series #861, edited by F. H. Case, P. and Alexandridis, ACS
Press, 2003.
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