Electrohydrodynamic Stresses from Hydrogen-Bond Network Dynamics in Water

Abstract

The resistance of hydrogen-bond networks to ambient flow in water produces viscoelectric stresses and contributes to electrostrictive pressure. Within Onsager's nonequilibrium thermodynamic framework, a lattice-gas description of aqueous electrolytes is combined with a coarse-grained hydrodynamic representation of hydrogen-bonded molecular networks, where viscous dissipation is modeled through energetically equivalent Brownian entities. This formulation connects molecular structural information from experiments and molecular dynamics to a unified dipolar Poisson-Nernst-Planck-Stokes (dPNP-S) continuum theory, quantitatively reproducing the measured viscoelectric coefficient of Jin et al. (PNAS 2022) and contributions to electrostrictive pressure. These results identify a microscopic mechanism by which hydrogen-bond dynamics influence electrohydrodynamic flow.

Figures (2)

• Figure 1: Schematics: (a) Electric-field-induced hydrogen-bond restructuring across molecular, cluster, and network scales. Colored spheres denote oxygen (red), hydrogen (light gray), and water clusters (dark gray); solid and dashed bonds indicate covalent and HB correlations. Arrows indicate structural orientation (black) electric field & induced rotation (blue), ambient flow (orange), and rotational diffusion (grey). (b) Coarse-grained Brownian-particle representation of the HB network embedded in a molecular lattice; sticks denote structural correlations between molecules (spheres). (Color online.)
• Figure 2: (a) Evolution of $\varepsilon_r/\varepsilon_{r0}$ and $f_v/f_{v0}$ from dPNP-S compared to LB-fitted transient viscoelastic models (LBFT-VE). Black arrows indicate the evolution from time $0.5$ to $5$ times of Debye timescale ($\tau_D$). (b) Electroosmotic mobility correction factor over PNP for different parametric cases (refer to the joint PRF submission), using different models. (Color online.)