IMX Seminar Series - Molecular origins of the zeta potential

Zeta-Potential (ZP, ζ) is among the key physical properties characterizing the behavior of nanoparticles in colloidal solutions because it represents a macroscopic property that carries a signature of the interfacial behavior (often attributed to electric double layer formation). One of the reasons behind its widespread utilization is the fact that it is (relatively) easily determined experimentally.
This presentation overviews our work devoted to the determination of ZP from molecular simulations. We focus on non-equilibrium molecular dynamics simulations of electroosmosis, which closely mimic the experimental approach [1,2]. In case of application of Electronic continuum correction (ECC) utilizing scaled charges of ions, the interaction of scaled charges with an external electric field must be adequately accounted [3].
We will discuss the implementation of these methods to Gromacs and LAMMPS simulation packages allowing non-equilibrium simulations of complex surfaces and molecules, as well as our postprocessing tool allowing analysis and determination of ZP from simulation trajectories.
While we focus on the description of the approaches, representative results document the role of the strength of surface adsorption and ion pairing on the observed electrokinetics, including anomalous behavior of ZP with surface charge (pH), explained by an overcompensation of the surface charge.

[1] M. Předota, M. Machesky, D. Wesolowski, “Molecular Origins of the Zeta Potential”, Langmuir, 32, 10189-10198 (2016) 
[2] D. Biriukov, P. Fibich, M. Předota, “Zeta Potential Determination from Molecular Simulations”, J. Phys. Chem. C, 124, 3159-3170 (2020)
[3] M. Předota, D. Biriukov, “Electronic Continuum Correction without Scaled Charges”, J. Mol. Liq, 314, 113571 (2020)

Bio: 1971Born in České Budějovice (Budweis), Czech Republic
1990-1995MSc. in Theoretical Physics (with honors),1995, Charles University in Prague, Faculty of Mathematics and Physics
MSc Thesis: “Study of surface growth”
1995-1998Ph.D. in Physical Chemistry, 1998, Charles University in Prague, Faculty of Science
Ph.D. thesis: “Water at the level of extended primitive models”
1998-2002Post-doctoral Research Associate (2001-2002 Senior Research Associate), Department of Chemical Engineering, University of Tennessee, Knoxville, USA
2002-2013Senior Research Scientist, Institute of Chemical Process Fundamentals, Prague, Academy of Sciences of the Czech Republic
2003-University of South Bohemia, Ceske Budejovice, Czech Republic
2003-2013   Dept. of Medical Physics and Biophysics, Department of Physics and Biophysics, Assistant Professor
2013-         Department of Physics, Faculty of Science, Associate Professor(doc.), habilitation:  Charles University in Prague, Faculty of Mathematics and Physics, field Physics - Physics of Molecular and Biological Structures. Habilitation thesis: “Computer simulations of solid-liquid interfaces”