Stefan Frijters, Florian Günther, Jens Harting
Both surfactants and nanoparticles are of interest as emulsifying agents, and
are being used in a great variety of industrial applications. Directly
comparing the effects of these different emulsifiers at microscopic scales
provides valuable insight into the physical processes involved. We present
three-dimensional numerical simulations, exploring this direct comparison
between surfactants and nanoparticles as additives at a fluid-fluid interface.
We study their respective effects on surface tensions and deformation
properties of droplets under shear. The chosen method for this study is the
well-established lattice Boltzmann method, extended to allow for amphiphiles
and solid particles. The limits of this method and its extensions are probed,
validating the use of lattice Boltzmann in this field of study. We recover
Taylor's law for small deformation of droplets when surfactant or particles are
added to the droplet interface. The effect of surfactant is captured in the
capillary number, leading to a collapse of the deformation curve over its
complete domain. Adsorped particles increase deformation at higher capillary
number and eventually lead to easier breakup of the droplet.
View original:
http://arxiv.org/abs/1201.6562
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