A novel droplet-based approach to study phase transformations in lyotropic liquid crystalline systems

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  • Vincent He
  • Victor J. Cadarso
  • Susanne Seibt
  • Boyd, Ben
  • Adrian Neild

Hypothesis: Lyotropic liquid crystals (LLC) and their phase transformations in response to stimuli have gathered much interest for controlled and ‘on-demand’ drug applications. Bulk methods of preparation impose limitations on studying the transformations, especially induced by compositional changes, such as enzymatic changes to lipid structure. Here we hypothesise that controlled microfluidic production and coalescence of dissimilar aqueous and lipid droplets emulsified in a third mutually immiscible liquid will provide a new approach to the spatio-temporal study of structure formation in lyotropic liquid crystalline materials. Experiments: Separate lipid and aqueous droplets, dispersed in a fluorocarbon oil were generated using a microfluidic format. The chip, prepared as a hybrid polydimethylsiloxane (PDMS) and glass microfluidic device, was constructed to enable in-situ acquisition of time-resolved synchrotron small angle X-ray scattering (SAXS) and crossed polarised light microscopy of the coalesced droplets to determine the structures present during aging. Findings: Janus-like droplets formed upon coalesce, with distinct lipid and aqueous portions with a gradient between the two sides of the merged droplet. SAXS and polarised light microscopy revealed a progression of mesophases as the lipid portion was hydrated by the aqueous portion via the diffusion limited interface which separated the portions. Thus demonstrating, on a droplet scale, a new approach for studying the phase transformation kinetics and identification of non-equilibrium phase in droplet-based lyotropic liquid systems.

Original languageEnglish
JournalJournal of Colloid and Interface Science
Volume641
Pages (from-to)459-469
ISSN0021-9797
DOIs
Publication statusPublished - 2023

Bibliographical note

Funding Information:
The SAXS studies were conducted on the SAXS/WAXS beamline at the Australian Synchrotron (ANSTO), Clayton, Victoria. This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF).

    Research areas

  • Cubic phase, Emulsion droplet, Hexagonal phase, Lipid self-assembly, Microfluidic system, Monoolein, Small angle X-ray scattering

ID: 341260932