Experimental Confirmation of Transformation Pathways between Inverse Double Diamond and Gyroid Cubic Phases

• A macroscopically oriented double diamond inverse bicontinuous cubic phase (Q(II)(D)) of the lipid glycerol monooleate is reversibly converted into a gyroid phase (Q(II)(G)). The initial Q(II)(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 Q(II)(D) sample by osmotic stress. This converts the Q(II)(D) phase into a Q(II)(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 Q(II)(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 Q(II)(G) phases, in particular with applications as nanomaterial templates.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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art (subject category)

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