Chemical Physics and Dynamics of Surfaces – Self-organization at the nanoscale – Topological defects in thin smectic films


  • Permanent members: Emmanuelle Lacaze, Sébastien Royer, Michel Goldmann
  • PhD Student: Jean de Dieu Niyonzima

Liquid crystal topological defects are among condensed matter topological defects the easiest to control for a deep study of defect structure and properties. We know now how to build arrays of quasi-periodic topological defects in thin liquid crystal smectic films. They are the response to the frustration that we impose through antagonistic geometries at the two interfaces, substrate and air. Combining Optical Microscopy, AFM, ellipsometry and synchrotron GISAXS, we are able to reconstruct the structure of the smectic layers with an unprecedented resolution for a nanoscale determination of the topological defects.

CaptionScheme of the smectic layers reconstructed around the toplogical defects and measured by Optical Microscopy (below), ellipsometry (above) and GISAXS (on the right).

We explore the nanoscale structure of the defects, their evolution close to the smectic/nematic transition and reveal different kinds of defects when the liquid crystal/substrate interactions are modified.


  • Delphine Coursault, “Decoration of linear smectic defects by gold nanoparticles”. Defense: march 2013
  • Laurent Pelliser, “Assembly and organization of semiconductor nanoparticles in topological defect networks in liquid crystal”. Defense: June 2016
  • Ian Nemitz (co-direction with Univ Cleveland, USA). Defense: November 2018
  • Syou P’heng Do, “Liquid crystal/nanoparticle composites, synergies between soft matter and electronic properties of nanoparticles”. Defense: January 2019


  • S. Kralj, L. Mesarec (Univ. Maribor-Slovenia)


  • Delphine Coursault, Bruno Zappone, Alessandro Coati, Athmane Boulaoued, Laurent Pelliser, et al.. Self-organized arrays of dislocations in thin smectic liquid crystal films. Soft Matter, Royal Society of Chemistry, 2016, 12 (3), pp.678-688. ⟨10.1039/C5SM02241J⟩. ⟨hal-01230908⟩
  • Piotr Sleczkowski, Ye Zhou, Supitchaya Iamsaard, Juan de Pablo, Nathalie Katsonis, et al.. Light-activated helical inversion in cholesteric liquid crystal microdroplets. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2018, 115 (17), pp.4334 – 4339. ⟨10.1073/pnas.1720742115⟩. ⟨hal-01843382⟩
  • I Nemitz, I. Gryn, N. Boudet, R. Lemieux, M. Goldmann, et al.. Observations of a streak texture in the hybrid-aligned smectic-C phase. Soft Matter, Royal Society of Chemistry, 2018, 14 (3), pp.460 – 469. ⟨10.1039/C7SM02129A⟩. ⟨hal-01688472⟩
  • Bruno Zappone, Atilla Eren Mamuk, Iryna Gryn, Valentina Arima, Alessandra Zizzari, et al.. Analogy between periodic patterns in thin smectic liquid crystal films and the intermediate state of superconductors. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2020, 117 (30), pp.17643-17649. ⟨10.1073/pnas.2000849117⟩. ⟨hal-03070716⟩