https://doi.org/10.1140/epjb/e2005-00137-0
Interfacial properties in solid-stabilized emulsions
1
Centre de Recherche Paul Pascal, CNRS, Avenue Schweitzer, 33600
Pessac, France
2
Laboratoire de Physicochimie Macromoléculaire, ESPCI, 10 rue
Vauquelin, 75231 Paris Cedex 05, France
3
Laboratoire des Milieux Dispersés Alimentaires, ISTAB, Avenue des
facultés, 33405 Talence, France
Corresponding author: a schmitt@crpp-bordeaux.cnrs.fr
Received:
15
December
2004
Published online:
28
April
2005
We prepared concentrated monodisperse oil-in-water emulsions stabilized by
solid particles. The osmotic resistance, Π, of the emulsions was measured for
different oil volume fractions above the random close packing (). The dimensionless osmotic resistance,
(γ being the
interfacial tension and R being the undeformed drop radius), was always
substantially higher than the corresponding values obtained for
surfactant-stabilized emulsions. It can be concluded that droplet
deformation in solid-stabilized emulsions is not controlled by the capillary
pressure,
, of the non-deformed droplets but rather by
,
being a parameter characterizing the rigidity of the droplets
surfaces. The data can be interpreted considering that the interfacial
layers are elastic at small deformations and exhibit plasticity at
intermediate deformations.
corresponds to the surface yield
stress, i.e. the transition between elastic and plastic regimes. We discuss the
origin of the surface behavior considering the strong lateral interactions
that exist between the adsorbed solid particles. We propose an independent
measurement of
based on the critical bulk stress that produces
droplet fragmentation in dilute emulsions submitted to shear. Finally, the
bulk shear elastic modulus was measured as a function of ϕ and confirms many
of the features revealed by the osmotic resistance.
PACS: 82.70.-y – Disperse systems; complex fluids / 82.70.Kj – Emulsions and suspensions / 68.15.+e – Liquid thin films
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005