Temperature-gradient-induced thermomigration in smectic liquid crystal bubbles and freely suspended films in microgravity
ORAL
Abstract
In-plane temperature gradients were applied to tethered smectic bubbles on the ISS during the OASIS mission and to thin freely-suspended smectic films during suborbital rocket flights in order to study the Marangoni effect in a 2D fluid in microgravity. Tethered bubbles of smectic A liquid crystal were inflated in a temperature-controlled chamber. An emulsion of islands subsequently generated on the bubble with an air jet was initially homogeneously distributed over the entire bubble surface. When the inflation syringe was heated, however, the islands moved away from the point of heating, with the island velocity decreasing as they migrated away from the syringe. The islands appear to be moving with the background film, not as a direct consequence of the thermal gradient. In flat films, on the other hand, in-plane temperature gradients were observed to cause two specific Marangoni effects, directed flow and convection patterns.
[1] T. Trittel, et al., Phys. Rev. Lett. 122, 234501 (2019) [2] R. Stannarius et al., New J. Phys. 21, 063033 (2019).
[1] T. Trittel, et al., Phys. Rev. Lett. 122, 234501 (2019) [2] R. Stannarius et al., New J. Phys. 21, 063033 (2019).
*This work was supported by NASA Grant No. NNX-13AQ81G and by the Soft Materials Research Center under NSF MRSEC Grant No. DMR-1420736, and by DLR Grants OASIS-Co 50WM1430 and 50WM1744 and DFG Grant STA 425/40.
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Presenters
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Noel Anthony Clark
- Physics and Soft Materials Research Center, University of Colorado Boulder
- University of Colorado, Boulder
- Department of Physics, University of Colorado, Boulder
- Physics and Soft Materials Research Center, University of Colorado