title: Why direct or reversed Hofmeister series? Interplay of hydration, non-electrostatic potentials, and ion size.
abstract: A modified Poisson-Boltzmann analysis is made of the double layer interaction between two silica surfaces and two alumina surfaces in chloride electrolyte. The analysis incorporates nonelectrostatic ion-surface dispersion interactions based on ab initio ionic excess polarizabilities with finite ion sizes. A hydration model for the tightly held hydration shell of kosmotropic ions is introduced. A direct Hofmeister series (K > Na > Li) is found at the silica surface while the reversed series (Li > Na > K) is found at alumina, bringing theory in line with experiment for the first time. Calculations with unhydrated ions also suggest that surface-induced dehydration may be occurring at the alumina surface.
authors.affiliation: Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia. Drew.Parsons@anu.edu.au
authors.forename: D F
authors.initials: DF
authors.lastname: Parsons
authors.forename: M
authors.initials: M
authors.lastname: Boström
authors.forename: T J
authors.initials: TJ
authors.lastname: Maceina
authors.forename: A
authors.initials: A
authors.lastname: Salis
authors.forename: B W
authors.initials: BW
authors.lastname: Ninham
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008672:Metals, Alkali / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D002712:Chlorides; D004573:Electrolytes; D008672:Metals, Alkali; D012492:Salts; D014867:Water; D012822:Silicon Dioxide; D000537:Aluminum Oxide