Team
- Permanent members: Emmanuelle Lacaze, Sébastien Royer
Liquid crystal topological defects are among condensed matter topological defects the easiest to control for a deep study of defect structure and properties. We study topological defect dynamics, the idea being to focus on liquid crystal films not impacted by any boundary. We thus either investigate free suspended smectic films or free floating smectic bubbles. These latter ones are measured through parabolic flight campaigns of CNES.
Caption: (a) Islands in the freely floating bubble measured in the CNES parabolic flight campaign of Oct 2020 (with a scheme showing in perspective the presence of dislocations by the red points. (b) Wrinkles appearing in a given island durong abrupt stress
In the bubbles we have evidenced wrinkle formation under abrupt stress that appear localized in thicker islands in relation with the presence of 1D smectic topological defects (dislocations) surrounding the islands. We show that this is related to the large line tension induced by the topological defects. We now explore the impact of the presence of nanoparticles trapped in the dislocations that may modify the island line tension.
Past PhD
- Amine Missaoui (co-direction avec Magdeburg Univ), ” Dynamique des défauts topologiques dans les films et bulles de cristaux liquides smectiques en suspension libre “. Défense : Mars 2021
Collaborations
- R. Stannarius/K. Harth/A. Emerin (Univ. Magdeburg – Germany)
- C. Rosenblatt/A. Missaoui (Univ. Cleveland – USA)
Funding
- CNES grant for A. Missaoui PHD
- CNES contracts “Défauts topologiques dans les cristaux liquides avec nanoparticules”
- CNES parabolic flights operated by Novespace in Oct. 2020 and Oct. 2021
Publication
- Amine Missaoui, Emmanuelle Lacaze, Alexey Eremin, Ralf Stannarius. Observation of Backflow during the Anihilation of Topologocal Defects in Freely Suspended Smectic Films. Crystals, MDPI, 2021, 11 (4), pp.430. ⟨10.3390/cryst11040430⟩. ⟨hal-03205186⟩
