title: Blending gelators to tune gel structure and probe anion-induced disassembly.
abstract: Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1- and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected α-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution.
authors.affiliation: Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE (UK).
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Foster
authors.forename: Robert M
authors.initials: RM
authors.lastname: Edkins
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Cameron
authors.forename: Neil
authors.initials: N
authors.lastname: Colgin
authors.forename: Katharina
authors.initials: K
authors.lastname: Fucke
authors.forename: Sam
authors.initials: S
authors.lastname: Ridgeway
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Crawford
authors.forename: Todd B
authors.initials: TB
authors.lastname: Marder
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby
authors.forename: Steven L
authors.initials: SL
authors.lastname: Cobb
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Steed
keywords: blend; co-gels; fluorescence; orthogonal self-assembly; supramolecular chemistry