Electric fields near undulating dielectric membranes

Nicholas Pogharian; Alexandre P Dos Santos; Ali Ehlen; Monica Olvera de la Cruz

doi:10.1063/5.0185570

Electric fields near undulating dielectric membranes

J Chem Phys. 2024 Mar 7;160(9):094704. doi: 10.1063/5.0185570.

Authors

Nicholas Pogharian¹, Alexandre P Dos Santos^{1

2}, Ali Ehlen³, Monica Olvera de la Cruz^{1

3

4

5

6}

Affiliations

¹ Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
² Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS, Brazil.
³ Applied Physics Program, Northwestern University, Evanston, Illinois 60208, USA.
⁴ Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
⁵ Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
⁶ Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.

PMID: 38426520
DOI: 10.1063/5.0185570

Abstract

Dielectric interfaces are crucial to the behavior of charged membranes, from graphene to synthetic and biological lipid bilayers. Understanding electrolyte behavior near these interfaces remains a challenge, especially in the case of rough dielectric surfaces. A lack of analytical solutions consigns this problem to numerical treatments. We report an analytic method for determining electrostatic potentials near curved dielectric membranes in a two-dimensional periodic "slab" geometry using a periodic summation of Green's functions. This method is amenable to simulating arbitrary groups of charges near surfaces with two-dimensional deformations. We concentrate on one-dimensional undulations. We show that increasing membrane undulation increases the asymmetry of interfacial charge distributions due to preferential ionic repulsion from troughs. In the limit of thick membranes, we recover results mimicking those for electrolytes near a single interface. Our work demonstrates that rough surfaces generate charge patterns in electrolytes of charged molecules or mixed-valence ions.