title: Ion transport controlled by nanoparticle-functionalized membranes.
abstract: From proton exchange membranes in fuel cells to ion channels in biological membranes, the well-specified control of ionic interactions in confined geometries profoundly influences the transport and selectivity of porous materials. Here we outline a versatile new approach to control a membrane's electrostatic interactions with ions by depositing ligand-coated nanoparticles around the pore entrances. Leveraging the flexibility and control by which ligated nanoparticles can be synthesized, we demonstrate how ligand terminal groups such as methyl, carboxyl and amine can be used to tune the membrane charge density and control ion transport. Further functionality, exploiting the ligands as binding sites, is demonstrated for sulfonate groups resulting in an enhancement of the membrane charge density. We then extend these results to smaller dimensions by systematically varying the underlying pore diameter. As a whole, these results outline a previously unexplored method for the nanoparticle functionalization of membranes using ligated nanoparticles to control ion transport.
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Barry
authors.affiliation: James Franck Institute, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: McBride
authors.affiliation: 1] James Franck Institute, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA [2] Department of Physics, University of Chicago, 5720 South Ellis Avenue, Chicago, Illinois 60637, USA.
authors.forename: Heinrich M
authors.initials: HM
authors.lastname: Jaeger
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Lin
mesh_terms: D000586:Amination; D001692:Biological Transport; D002264:Carboxylic Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017136:Ion Transport; D007700:Kinetics; D008567:Membranes, Artificial; D053768:Metal Nanoparticles / Q000737:chemistry*; D008745:Methylation; D016062:Porosity; D055672:Static Electricity
chemical_list: D002264:Carboxylic Acids; D008567:Membranes, Artificial; D006046:Gold