title: Theory of collective proton motion at interfaces with densely packed protogenic surface groups.
abstract: We present a theoretical study of collective proton transport at a 2D array of end-grafted protogenic surface groups with sulfonic acid head groups. The graft positions of the surface groups form a regular hexagonal lattice. We consider the interfacial array at a high packing density of the surface groups and under minimal hydration with one water molecule added per head group. For these conditions, the stable interfacial conformation consists of a bicomponent lattice of hexagonally ordered sulfonate anions and interstitial hydronium cations. Hydronium ion motion occurs as a travelling solitary wave. We analyse the microscopic parameters of the solitons and study the influence of different potential profiles on the proton motion created by rotation and tilting of sidechains and sulfonate anions. Using soliton solutions of the equation of motion, we establish relations between the energy and mobility of the solitons and the microscopic structural and interaction parameters of the array.
authors.affiliation: Department of Chemistry, Simon Fraser University, 8888 University drive, Burnaby, BC, V5A 1S6, Canada. agolovne@sfu.ca
authors.forename: Anatoly
authors.initials: A
authors.lastname: Golovnev
authors.forename: Michael
authors.initials: M
authors.lastname: Eikerling
mesh_terms: D001692:Biological Transport; D001703:Biophysics / Q000379:methods; D004573:Electrolytes; D007477:Ions; D007700:Kinetics; D015233:Models, Statistical; D008962:Models, Theoretical; D056004:Molecular Dynamics Simulation; D009038:Motion; D009861:Onium Compounds / Q000737:chemistry; D011522:Protons; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D004573:Electrolytes; D007477:Ions; D009861:Onium Compounds; D011522:Protons; D012996:Solutions; D014867:Water; C027727:hydronium ion