title: Selective Permeability of Uranyl Peroxide Nanocages to Different Alkali Ions: Influences from Surface Pores and Hydration Shells.
abstract: The precise guidance to different ions across the biological channels is essential for many biological processes. An artificial nanopore system will facilitate the study of the ion-transport mechanism through nanosized channels and offer new views for designing nanodevices. Herein we reveal that a 2.5 nm-sized, fullerene-shaped molecular cluster Li48+m K12(OH)m [UO2(O2)(OH)]60-(H2O)n (m ≈ 20 and n ≈ 310) (U60) shows selective permeability to different alkali ions. The subnanometer pores on the water-ligand-rich surface of U60 are able to block Rb(+) and Cs(+) ions from passing through, while allowing Na(+) and K(+) ions, which possess larger hydrated sizes, to enter the interior space of U60. An interestingly high entropy gain during the binding process between U60 and alkali ions suggests that the hydration shells of Na(+)/K(+) and U60 are damaged during the interaction. The ion selectivity of U60 is greatly influenced by both the morphologies of the surface nanopores and the dynamics of the hydration shells.
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH, 44325 (USA).
authors.forename: Yunyi
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH, 44325 (USA).
authors.forename: Fadi
authors.initials: F
authors.lastname: Haso
authors.affiliation: Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN 46556 (USA).
authors.forename: Jennifer E S
authors.initials: JE
authors.lastname: Szymanowski
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH, 44325 (USA).
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH, 44325 (USA).
authors.forename: Lang
authors.initials: L
authors.lastname: Hu
authors.affiliation: Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN 46556 (USA). pburns@nd.edu.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burns
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH, 44325 (USA). tliu@uakron.edu.
authors.forename: Tianbo
authors.initials: T
authors.lastname: Liu
keywords: actinides; hydration shell; ion selectivity; nanopores; self-assembly