Quenched charge disorder and Coulomb interactions

Area of Science:

• Physics
• Physical Chemistry
• Materials Science

Background:

• Charged surfaces in ionic fluids exhibit complex electrostatic interactions.
• Understanding these interactions is crucial for colloid science, biomolecular assembly, and nanotechnology.
• Disorder in surface charge distribution is a common feature in real systems.

Purpose of the Study:

• To develop a general theoretical framework for analyzing quenched fixed charge disorder effects.
• To investigate the impact of disorder on effective electrostatic interactions in a one-component Coulomb fluid.
• To explore both mean-field and strong-coupling regimes.

Main Methods:

• Development of a general formalism for quenched fixed charge disorder.
• Analytical derivation of results in two asymptotic limits: mean-field (Poisson-Boltzmann with Gaussian fluctuations) and strong-coupling.
• Application to ideally polarizable planar surfaces with equal mean surface charge.

Main Results:

• Disorder has no effect on mean-field interactions; surfaces repel.
• In the strong-coupling limit, disorder adds to the free energy, inducing enhanced long-range attraction.
• Increased disorder strength reduces equilibrium interplate distance, suggesting a disorder-driven collapse.

Conclusions:

• Quenched fixed charge disorder plays a critical role in mediating electrostatic interactions, particularly in the strong-coupling regime.
• Disorder can overcome repulsive forces and drive attractive interactions, leading to phenomena like surface collapse.
• The developed formalism provides a valuable tool for predicting the behavior of charged surfaces in disordered environments.