Colloids and Disperse System

Our research is concentrated on an unified , phenomenological description of colloid particle inferaction and irreversible adsorption at solid/liquid interfaces. Our primary goal is to characterize quantitatively the role of various force fields such as hydrodynamic, external (gravity) and specific (dispersion and electrostatic interactions) in colloid adsorption phenomena. We are also interested in discovering the link between irreversible and reversible systems and determining the range of applicability of equilibrium statistical-mechanical theories to colloid systems.

MAIN RESEARCH TOPICS

  • Convective diffusion of interacting colloid particles.
  • Electrostatic double-layer interactions during particle adsorption and kinetics of irreversible adsorption at solid/liquid interfaces.
  • Dynamic surface tension of ionic surfactants.
  • Structure and density fluctuations in adsorbed layers.
  • Streaming potential of surfaces covered with particles.

METHODS

  • Generalized finite-difference numerical method adopted for parabolic type , partial differential equations with non-linear boundary conditions.,
  • Over-relaxation and iteration approach for solving the Poisson-Boltzmann (electrostatic) and the Navier-Stokes (hydrodynamic) equations.
  • Monte-Carlo simulations of particle adsorption kinetics and jamming coverage.
  • Brownian-Dynamics simulations of particle adsorption under combined hydrodynamic, electrostatic and gravity force fields.
  • Direct, in situ microscope measurements of particle adsorption combined with real time image analysis.
  • Streaming potential measurements combined with AFM and SEM methods for particle coverage determination.
  • Tensammetric and the drop weight methods for determining adsorption kinetics at liquid/liquid and liquid/air interfaces.

MAIN ACHIEVEMENTS

  • Generalization of Levich's convective diffusion theory,
  • Discovery and experimental confirmation of the "inverse salt" effect consisting in the increase of particle adsorption rate upon decreasing ionic strength.
  • Generalization of the Random Sequential Adsorption (RSA) model to polydisperse and nonspherical particles.
  • Proper description of particle adsorption phenomena at partially covered surfaces.
  • Direct experimental determination of the 2D fluctuation phenomena and radial distribution functions of adsorbed particles (see Fig. ).


 

 

   

MAIN RESEARCH TOPICS

  • Theoretical and experimental studies of adsorption of colloids and proteins at solid/liquid interfaces
  • Modeling of electrostatic interaction of colloid particle
  • Transport of nanoparticles through porous media
  • Self-assembling and structure of colloid particle multilayer

METHODS

  • Atomic force microscopy,
  • Optical microscopy,
  • Rotating disk electrode

MAIN ACHIEVEMENTS

  • Development of a priori theoretical model of charged colloid particle adsorption without fitting parameters

Fig. 2. Colloid particle multilayer simulated at solid/liquid interface

Fig. 2. Comparison of theoretically and experimentally determined pair-correlation function for a monolayer of spherical nanoparticles