Dynamics of charged and porous colloidal particles in concentrated suspensions

Gerhard Nagele (Julich - Germany)

Dispersions of charged and porous colloidal particles are of fundamental interest in chemical industry, biology and food science. We explore the short-time and long-time dynamics of well-characterized model systems using simulation methods and many-body theory, in conjunction with dynamic scattering experiments. Transport properties are discussed including the effective shear viscosity, generalized sedimentation coefficient and various diffusion coefficients [1]. We scrutinize the validity of generalized Stokes-Einstein relations between diffusion and rheological properties [2]. A far-reaching dynamic scaling behavior relating long-time to short-time dynamics, and wavenumber-dependent diffusion to self-diffusion, is shown to apply approximately to charged colloids [3]. The universality of the experimentally observed scaling behavior is analyzed theoretically by mode-coupling theory and Brownian dynamics simulations. Moreover, results of a novel simulation study on the dynamics in dense sus-pensions of solvent-permeable spheres are presented, with a high-precision account of many-body hydrodynamic interactions [4]. Our study gives new insights into the generic behavior of porous-particle dispersions.

[1] M. Heinen, A.J. Banchio, P. Holmqvist and G. Nagele, J. Appl. Cryst. 43, 970 (2010).

[2] A.J. Banchio and G. Nagele, J. Chem. Phys. 128, 104903 (2008).

[3] P. Holmqvist and G. Nagele, Phys. Rev. Lett. 104, 058301 (2010).

[4] G.C. Abade, B. Cichocki, M.L. Ekiel, G. Nagele and E. Wajnryb, J. Chem. Phys. 132, 014503 and 133, 084906 (2010); J. Phys.: Condens. Matter 22, 322101 (2010).

Back to Seminar Home Page

Last modified 01-October-2010 by website owner: NCNR (attn: )