title: Fluorous 'ponytails' lead to strong gelators showing thermally induced structure evolution.
abstract: Appending perfluoroalkyl substituents to bis(urea) gelators results in significantly decreased inter-chain interactions with markedly thinner fibres and hence more cross-linked and more transparent gels with potential applications in the crystallisation of fluorinated pharmaceuticals. Gel structure has been probed by detailed SANS measurements which indicate a surprising structure evolution on thermal cycling, not seen for hydrocarbon analogues. The SANS data are complemented by the single crystal X-ray structure of one fluorinated gelator.
authors.affiliation: James L. Winkle College of Pharmacy, University of Cincinnati, 3225 Eden Avenue, Cincinnati, OH, USA. kumariha@ucmail.uc.edu.
authors.forename: Harshita
authors.initials: H
authors.lastname: Kumari
authors.affiliation: Department of Chemistry, Durham University, South Road, Durham DH1 3LE, UK. jon.steed@durham.ac.uk.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Armitage
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Kline
authors.affiliation: Department of Chemistry, Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Damodaran
authors.affiliation: Department of Chemistry, Durham University, South Road, Durham DH1 3LE, UK. jon.steed@durham.ac.uk.
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Kennedy
authors.affiliation: Department of Chemistry, University of Missouri - Columbia, 601 South College Avenue, Columbia, MO 65211, USA.
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Atwood
authors.affiliation: Department of Chemistry, Durham University, South Road, Durham DH1 3LE, UK. jon.steed@durham.ac.uk.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Steed
mesh_terms: D018360:Crystallography, X-Ray; D005466:Fluorocarbons / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D008422:Materials Testing; D033363:Neutron Diffraction; D053838:Scattering, Small Angle; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D005466:Fluorocarbons; D005782:Gels; D014508:Urea