title: Tuning structure and mobility of solvation shells surrounding tracer additives.
abstract: Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions are rationally modified to affect corresponding solvation structure. For tracers in a dense hard-sphere fluid, we compare two types of tracer-solvent interactions: (1) a hard-sphere-like interaction, and (2) a soft repulsion extending beyond the hard core designed via statistical mechanical theory to enhance tracer mobility at infinite dilution by suppressing coordination-shell structure [Carmer et al., Soft Matter 8, 4083-4089 (2012)]. For the latter case, we show that the mobility of surrounding solvent particles is also increased by addition of the soft repulsive interaction, which helps to rationalize the mechanism underlying the tracer's enhanced diffusivity. However, if multiple tracer surfaces are in closer proximity (as at higher tracer concentrations), similar interactions that disrupt local solvation structure instead suppress the position-dependent solvent dynamics.
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: James
authors.initials: J
authors.lastname: Carmer
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Avni
authors.initials: A
authors.lastname: Jain
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Bollinger
authors.affiliation: Sandia National Laboratories, Department 1814, P.O. Box 5800, Albuquerque, New Mexico 87185, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: van Swol
authors.affiliation: McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Truskett
mesh_terms: D004058:Diffusion; D019277:Entropy; D057446:Hydrodynamics; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D012997:Solvents / Q000737:chemistry*; D013269:Stochastic Processes
chemical_list: D012997:Solvents