The intimate relationship between the dielectric response and the decay of intermolecular correlations and surface forces in electrolytes

Abstract

The simultaneous monotonic and oscillatory decay modes for interactions in ionic liquids and electrolyte solutions are analysed and physically explained.

Correlation Length in Concentrated Electrolytes: Insights from All-Atom Molecular Dynamics Simulations

“…28 The lower exponent (and corresponding smaller decay length) is, however, in good agreement with previous theoretical results, with reported exponents ranging between 1 and 2. 34,36,37,39 As an illustration of such predictions of liquid state theories, Fig.4 We note that in the high-concentration regime, all the theoretical decay lengths correspond to an oscillatory decay, while no such oscillations are observed in the experimental force profiles. However, it should be remembered here that surface force experiments do not directly measure the bulk correlation length, but forces between confined interfaces.…”

“…37 Finally, within this current environment, Kjellander further expanded his Dressed Ion Theory in an attempt to describe the experimental observations. 38,39 At present, however, it cannot be ruled out that liquid state theories based on simple descriptions of electrolytes such as the (restricted) primitive model cannot correctly capture the behavior of experimental systems. In reality, "chemical" complexities arise due to the atomistic and molecular nature of complex ions and solvents and their many degrees of freedom.…”

Bulk ionic screening lengths from extremely large-scale molecular dynamics simulations

“…We finish by noting that, so far, there is no theory of bulk ionic systems consistent with underscreening and cubic scaling (eqn (1) with a = 3). [38][39][40][41] Interestingly, most recent SFB results, while showing extremely large decay lengths, have demonstrated inconsistencies with the cubic scaling for [EMIM] + [EtSO 4 ] À . 42,43 Furthermore, to our knowledge, only one atomic force microscopy (AFM) study 44 reported underscreening, and only at elevated temperatures, while other AFM measurements have not.…”

Forces between silica particles in isopropanol solutions of 1:1 electrolytes

“…We suspect that the transition from monotonic to the oscillatory behavior is the Kirkwood crossover [60,61]. Recently, different theoretical and simulation approaches were used to study this transition [32,[35][36][37][38]60,62]. These approaches predict the transitions at salt concentrations corresponding to κd ∼ 1 to 2, where d is the mean ion diameter.…”

“…It was further observed that, at high concentrations of electrolytes, the transition from monotonic to oscillatory forces is present [31] and that the wavelengths of these oscillations can be abruptly changed by varying solvent composition [23]. These experiments sparked a renewed interest in theoretical description of ionic fluids, and a variety of theoretical approaches were utilized to describe these new exciting experimental data [32][33][34][35][36][37][38]. Measurements mentioned above have been performed using a SFA where one typically uses mica as a surface.…”