Speaker: David Andelman, School of Physics, Tel Aviv University, Israel
Abstract:
The Poisson-Boltzmann theory originates from the pioneering works of Debye and Onsager and
remains, to this day, the benchmark for ionic solutions and electrified interfaces. It has been
instrumental in predicting charge distributions and interactions between charged surfaces,
membranes, electrodes, macromolecules, and colloids over the last century. The electrostatic
model of charged fluids, on which the Poisson-Boltzmann description rests, and its statistical
mechanical consequences have been scrutinized in great detail. However, much less is
understood about its probable shortcomings when dealing with various aspects of real physical,
chemical, and biological systems. After reviewing the Poisson-Boltzmann theory, I will discuss
several recent extensions and modifications as applied to ions and macromolecules in solutions.
These novel ideas encompass the effects of dipolar solvent molecules, the finite size of ions,
ionic specificity, surface tension, charge regulation of ionizable groups, and the conductivity of
concentrated ionic solutions.