|
|
||
|
|
|
|
FROM:
Kirsten Harth (1,2), Torsten Trittel (1), Kathrin May (1) and Ralf Stannarius (1)
(1) Institute of Physics, Otto von Guericke University, Universitätsplatz 2, D-39106 Magdeburg, Germany
(2) Universiteit Twente, Physics of Fluids and Max Planck Center for Complex Fluid Dynamics, 7500 AE Enschede, The Netherlands
“Dynamic wrinkling of freely floating smectic films”, Soft Matter, Vol. 15, No. 34, pp 6769-6778, 5 July 2019, DOI: 10.1039/C9SM01181A
ABSTRACT: We demonstrate spontaneous wrinkling as a transient dynamical pattern in thin freely floating smectic liquid-crystalline films. The peculiarity of such films is that, while behaving liquid-like with respect to flow in the film plane, they cannot quickly expand their thickness because that requires stacking of additional smectic layers. At short time scales, they therefore behave like quasi-incompressible membranes, very different from soap films. Smectic films can develop a transient undulation instability or form bulges in response to lateral compression. Optical experiments with freely floating bubbles on parabolic flights and in ground lab experiments are reported. The characteristic wavelengths of the wrinkles are in the submillimeter range. We demonstrate the dynamic nature of the pattern formation mechanism and develop a basic model that explains the physical mechanism for the wavelength selection and wrinkle orientation.
Page 263 / 360