Bending nematic liquid crystal membranes with phospholipids

Jenieve Cumberland, Tetiana Lopatkina, Matthew Murachver, Piotr Popov, Viktor Kenderesi, A. Buka, Elizabeth K. Mann, Antal Jákli

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Abstract

The interactions of phospholipids with liquid crystals have formed the basis for attractive biosensor technologies, but many questions remain concerning the basic physics and chemistry of these interactions. Phospholipids such as 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), at sufficiently high (∼1 μM) concentrations and/or sufficiently long times, turn the liquid crystal director perpendicular to the LC/water interface. If the other side of the LC film is in contact with a surface that prefers perpendicular alignment, the LC film appears completely dark between crossed polarizers. Recently, however, Popov et al. (J. Mater. Chem. B, 2017, 5, 5061) noted that at even higher (∼10 μM) DLPC concentrations, the liquid crystal texture brightens again between crossed polarizers. To explain this surprising observation, it was suggested that the LC interface might bend. In this paper we show by optical surface profiler measurements that indeed the interface of the LC film of 4-cyano-4′-octylbiphenyl (8CB) suspended in a transmission electron microscopy (TEM) grid with openings of ∼0.5 mm in diameter bends towards the lipid-coated interface. We demonstrate that where the bending occurs, the bent interface exhibits extreme sensitivity to air pressure variations, producing an optical response with acoustic stimulation. Finally, we suggest a physical mechanism for this astonishing result.

Original languageEnglish
Pages (from-to)7003-7008
Number of pages6
JournalSoft Matter
Volume14
Issue number34
DOIs
Publication statusPublished - Jan 1 2018

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ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics

Cite this

Cumberland, J., Lopatkina, T., Murachver, M., Popov, P., Kenderesi, V., Buka, A., Mann, E. K., & Jákli, A. (2018). Bending nematic liquid crystal membranes with phospholipids. Soft Matter, 14(34), 7003-7008. https://doi.org/10.1039/c8sm01193a