title: Experimental confirmation of transformation pathways between inverse double diamond and gyroid cubic phases.
abstract: A macroscopically oriented double diamond inverse bicontinuous cubic phase (QII(D)) of the lipid glycerol monooleate is reversibly converted into a gyroid phase (QII(G)). The initial QII(D) phase is prepared in the form of a film coating the inside of a capillary, deposited under flow, which produces a sample uniaxially oriented with a ⟨110⟩ axis parallel to the symmetry axis of the sample. A transformation is induced by replacing the water within the capillary tube with a solution of poly(ethylene glycol), which draws water out of the QII(D) sample by osmotic stress. This converts the QII(D) phase into a QII(G) phase with two coexisting orientations, with the ⟨100⟩ and ⟨111⟩ axes parallel to the symmetry axis, as demonstrated by small-angle X-ray scattering. The process can then be reversed, to recover the initial orientation of QII(D) phase. The epitaxial relation between the two oriented mesophases is consistent with topology-preserving geometric pathways that have previously been hypothesized for the transformation. Furthermore, this has implications for the production of macroscopically oriented QII(G) phases, in particular with applications as nanomaterial templates.
authors.affiliation: H. H. Wills Physics Laboratory, University of Bristol , Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
authors.forename: Annela M
authors.initials: AM
authors.lastname: Seddon
authors.forename: James
authors.initials: J
authors.lastname: Hallett
authors.forename: Charlotte
authors.initials: C
authors.lastname: Beddoes
authors.forename: Tomás S
authors.initials: TS
authors.lastname: Plivelic
authors.forename: Adam M
authors.initials: AM
authors.lastname: Squires