title: Supramolecular gating of ion transport in nanochannels.
abstract: Several covalent strategies towards surface charge-reversal in nanochannels have been reported with the purpose of manipulating ion transport. However, covalent routes lack dynamism, modularity and post-synthetic flexibility, and hence restrict their applicability in different environments. Here, we introduce a facile non-covalent approach towards charge-reversal in nanochannels (<10 nm) using strong charge-transfer interactions between dicationic viologen (acceptor) and trianionic pyranine (donor). The polarity of ion transport was switched from anion selective to ambipolar to cation selective by controlling the extent of viologen bound to the pyranine. We could also regulate the ion transport with respect to pH by selecting a donor with pH-responsive functional groups. The modularity of this approach further allows facile integration of various functional groups capable of responding to stimuli such as light and temperature to modulate the transport of ions as well as molecules.
authors.affiliation: Nanomaterials and Catalysis Lab, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore 560064 (India) http://www.jncasr.ac.in/eswar/
authors.forename: B V V S Pavan
authors.initials: BV
authors.lastname: Kumar
authors.forename: K Venkata
authors.initials: KV
authors.lastname: Rao
authors.forename: S
authors.initials: S
authors.lastname: Sampath
authors.forename: Subi J
authors.initials: SJ
authors.lastname: George
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Eswaramoorthy
mesh_terms: D017136:Ion Transport; D017736:Ion-Selective Electrodes; D049329:Nanostructures / Q000737:chemistry*
keywords: charge-transfer; electrostatic gating; ion-selective channels; mesoporous materials; supramolecular chemistry