• Categoría: Artículo
  • Título: Evidence of electrostatic-enhanced depletion attraction in the structural properties and phase behavior of binary charged colloidal suspensions
  • Autor (es): G. J. Ojeda-Mendoza, A. Moncho-Jorda, P. González-Mozuelos, C. Haro-Pérez and L.F. Rojas-Ochoa
  • Revista: Soft Matter
  • Volumen: 14
  • Páginas: 1355
  • Formato: Enlace
  • Subido por: Catalina Ester

Evidence of electrostatic-enhanced depletion attraction in the structural properties and phase behavior of binary charged colloidal suspensions

G. J. Ojeda-Mendoza, A. Moncho-Jorda, P. González-Mozuelos, C. Haro-Pérez and L.F. Rojas-Ochoa

In this paper we study the structure and phase behavior of binary mixtures of charged particles at low
ionic strength. Due to the large size asymmetry between both species, light scattering measurements
give us access only to the partial static structure factor that corresponds to the big particles. We observe
that the addition of small charged colloids produces a decrease of the main peak of the measured static
structure factor and a shift to larger scattering vector values. This finding is in agreement with theory
based on integral equations with the Hypernetted-Chain Closure (HNC) relation. The effective interaction
between two big particles due to the presence of small particles is obtained by a HNC inversion scheme
and used in numerical simulations that adequately reproduce the experiments. We find that the presence
of small particles induces an electrostatic depletion screening among the big colloids, creating around
them an exclusion zone for the small charged colloids greater than that caused in the case of neutral
small colloids, which in turn augments the depletion effect.