title: Molecular valves for controlling gas phase transport made from discrete ångström-sized pores in graphene.
abstract: An ability to precisely regulate the quantity and location of molecular flux is of value in applications such as nanoscale three-dimensional printing, catalysis and sensor design. Barrier materials containing pores with molecular dimensions have previously been used to manipulate molecular compositions in the gas phase, but have so far been unable to offer controlled gas transport through individual pores. Here, we show that gas flux through discrete ångström-sized pores in monolayer graphene can be detected and then controlled using nanometre-sized gold clusters, which are formed on the surface of the graphene and can migrate and partially block a pore. In samples without gold clusters, we observe stochastic switching of the magnitude of the gas permeance, which we attribute to molecular rearrangements of the pore. Our molecular valves could be used, for example, to develop unique approaches to molecular synthesis that are based on the controllable switching of a molecular gas flux, reminiscent of ion channels in biological cell membranes and solid-state nanopores.
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Luda
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Lee W
authors.initials: LW
authors.lastname: Drahushuk
authors.affiliation: Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: Lauren
authors.initials: L
authors.lastname: Cantley
authors.affiliation: Department of Physics, National University of Singapore, Singapore 117542, Singapore.|National University of Singapore, Center for Advanced 2D Materials and Graphene Research Centre, Singapore 117546, Singapore.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Koenig
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Xinghui
authors.identifier: http://orcid.org/0000-0003-1097-7117
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: John
authors.initials: J
authors.lastname: Pellegrino
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Strano
authors.affiliation: Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA.|Division of Materials Science and Engineering, Boston University, Brookline, Massachusetts 02446, USA.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Bunch