title: Spherical monovalent ions at aqueous liquid-vapor interfaces: interfacial stability and induced interface fluctuations.
abstract: Ion-specific interfacial behaviors of monovalent halides impact processes such as protein denaturation, interfacial stability, and surface tension modulation, and as such, their molecular and thermodynamic underpinnings garner much attention. We use molecular dynamics simulations of monovalent anions in water to explore effects on distant interfaces. We observe long-ranged ion-induced perturbations of the aqueous environment, as suggested by experiment and theory. Surface stable ions, characterized as such by minima in potentials of mean force computed using umbrella sampling MD simulations, induce larger interfacial fluctuations compared to nonsurface active species, conferring more entropy approaching the interface. Smaller anions and cations show no interfacial potential of mean force minima. The difference is traced to hydration shell properties of the anions, and the coupling of these shells with distant solvent. The effects correlate with the positions of the anions in the Hofmeister series (acknowledging variations in force field ability to recapitulate essential underlying physics), suggesting how differences in induced, nonlocal perturbations of interfaces may be related to different specific-ion effects in dilute biophysical and nanomaterial systems.
authors.affiliation: Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States.
authors.forename: Shuching
authors.initials: S
authors.lastname: Ou
authors.forename: Yuan
authors.initials: Y
authors.lastname: Hu
authors.forename: Sandeep
authors.initials: S
authors.lastname: Patel
authors.forename: Hongbin
authors.initials: H
authors.lastname: Wan
mesh_terms: D000465:Algorithms; D000838:Anions / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D019277:Entropy; D005740:Gases / Q000737:chemistry*; D007455:Iodine / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013995:Time; D014867:Water / Q000737:chemistry
chemical_list: D000838:Anions; D002412:Cations; D002712:Chlorides; D005740:Gases; D012996:Solutions; D012997:Solvents; D014867:Water; D007455:Iodine; D012964:Sodium; D010100:Oxygen
references.citation: J Phys Chem B. 2005 Sep 29;109(38):17957-66
references.pmid: 16853305
references.citation: J Phys Chem B. 2008 Sep 18;112(37):11679-93
references.pmid: 18712908
references.citation: J Chem Theory Comput. 2012 Nov 13;8(11):3998-4003
references.pmid: 23185141
references.citation: Annu Rev Phys Chem. 2012;63:401-18
references.pmid: 22404593
references.citation: Proc Natl Acad Sci U S A. 2008 Nov 4;105(44):16928-33
references.pmid: 18957546
references.citation: Annu Rev Chem Biomol Eng. 2011;2:147-71
references.pmid: 22432614
references.citation: Faraday Discuss. 2009;141:161-73; discussion 175-207
references.pmid: 19227357
references.citation: Science. 2010 May 21;328(5981):1006-9
references.pmid: 20489020
references.citation: Science. 2005 Jan 28;307(5709):563-6
references.pmid: 15681380
references.citation: Proc Natl Acad Sci U S A. 2010 Apr 27;107(17):7716-21
references.pmid: 20385834
references.citation: J Phys Chem A. 2008 Dec 4;112(48):12378-84
references.pmid: 19006284
references.citation: Proc Natl Acad Sci U S A. 2012 Oct 30;109(44):17807-13
references.pmid: 22778442
references.citation: Phys Rev Lett. 2011 Dec 23;107(26):267801
references.pmid: 22243182
references.citation: J Chem Phys. 2010 Jan 14;132(2):024911
references.pmid: 20095713
references.citation: J Phys Chem B. 2013 May 30;117(21):6512-23
references.pmid: 23537166
references.citation: J Chem Phys. 2011 May 14;134(18):184507
references.pmid: 21568521
references.citation: J Comput Chem. 2005 Dec;26(16):1781-802
references.pmid: 16222654
references.citation: Chem Phys Lett. 2012 Feb 27;527:22-26
references.pmid: 23136448
references.citation: J Phys Chem B. 2010 Feb 11;114(5):1954-8
references.pmid: 20055377
references.citation: Biophys J. 1996 Oct;71(4):2056-63
references.pmid: 8889180
references.citation: J Am Chem Soc. 2012 Oct 24;134(42):17574-81
references.pmid: 23003674
references.citation: J Phys Chem B. 2005 Apr 7;109(13):6422-9
references.pmid: 16851715
references.citation: Phys Chem Chem Phys. 2012 Feb 14;14(6):1892-906
references.pmid: 22231014
references.citation: J Comput Chem. 2009 Jul 30;30(10):1545-614
references.pmid: 19444816
references.citation: J Chem Phys. 2008 Apr 14;128(14):144110
references.pmid: 18412426
references.citation: J Phys Chem B. 2006 Feb 23;110(7):3308-22
references.pmid: 16494345
references.citation: J Chem Phys. 2007 Aug 14;127(6):064509
references.pmid: 17705614
references.citation: Angew Chem Int Ed Engl. 2011 Jan 10;50(2):352-3
references.pmid: 21132822
references.citation: Langmuir. 2011 Apr 5;27(7):3588-99
references.pmid: 21355574
references.citation: J Comput Chem. 2012 Feb 5;33(4):453-65
references.pmid: 22109354
references.citation: J Chem Phys. 2012 Oct 21;137(15):154701
references.pmid: 23083178
references.citation: J Chem Phys. 2009 Aug 28;131(8):084709
references.pmid: 19725623
references.citation: J Chem Phys. 2013 Mar 21;138(11):114709
references.pmid: 23534655
references.citation: J Chem Phys. 2010 Jan 14;132(2):024713
references.pmid: 20095700
references.citation: J Phys Chem B. 2008 May 15;112(19):6187-92
references.pmid: 18229916
references.citation: Angew Chem Int Ed Engl. 2007;46(46):8907-11
references.pmid: 17943936
references.citation: Science. 2008 Feb 29;319(5867):1197-8
references.pmid: 18309069
references.citation: Science. 1951 Dec 21;114(2973):670-2
references.pmid: 17770191
references.citation: J Phys Chem B. 2012 May 3;116(17):5242-50
references.pmid: 22480309
references.citation: Proc Natl Acad Sci U S A. 2012 Jan 17;109(3):701-5
references.pmid: 22233805
references.citation: Proc Natl Acad Sci U S A. 2009 Sep 8;106(36):15125-30
references.pmid: 19720991
references.citation: J Phys Chem B. 2006 Nov 30;110(47):23987-94
references.pmid: 17125368
references.citation: J Chem Theory Comput. 2009 Feb 10;5(2):359-373
references.pmid: 23133341
references.citation: J Am Chem Soc. 2010 Jun 23;132(24):8248-9
references.pmid: 20518523
references.citation: J Chem Phys. 2012 Mar 28;136(12):124103
references.pmid: 22462831
references.citation: J Chem Theory Comput. 2010;6(3):774-786
references.pmid: 20300554
references.citation: Phys Chem Chem Phys. 2007 Jun 21;9(23):2959-67
references.pmid: 17551619