Understanding Depletion Induced Like-Charge Attraction from Self-Consistent Field Model. (3rd May 2017)

• Record Type: Journal Article
• Authors: Liu, Pei; Ma, Manman; Xu, Zhenli
• Is Part Of: Communications in computational physics. Volume 22:Number 1(2017:Jul.)
• Page Start: 95
• Page End: 111
• Publication Date: 2017-05-03
• Subjects: 82.45.Un, -- 64.70.pv, -- 82.60.Lf; Like-charge attraction, -- self-consistent field model, -- dielectric-boundary effect, -- correlation energy, -- Green's function; Mathematical physics -- Data processing -- Periodicals; Physics -- Data processing -- Periodicals; 530.150285
• DOI: 10.4208/cicp.OA-2016-0104
• Languages: English
• ISSNs: 1815-2406

Abstract

Abstract: The interaction force between likely charged particles/surfaces is usually repulsive due to the Coulomb interaction. However, the counterintuitive like-charge attraction in electrolytes has been frequently observed in experiments, which has been theoretically debated for a long time. It is widely known that the mean field Poisson-Boltzmann theory cannot explain and predict this anomalous feature since it ignores many-body properties. In this paper, we develop efficient algorithm and perform the force calculation between two interfaces using a set of self-consistent equations which properly takes into account the electrostatic correlation and the dielectric-boundary effects. By solving the equations and calculating the pressure with the Debye-charging process, we show that the self-consistent equations could be used to study the attraction between like-charge surfaces from weak-coupling to mediate-coupling regimes, and that the attraction is due to the electrostatics-driven entropic force which is significantly enhanced by the dielectric depletion of mobile ions. A systematic investigation shows that the interaction forces can be tuned by material permittivity, ionic size and valence, and salt concentration, and that the like-charge attraction exists only for specific regime of these parameters.