Ordering of binary colloidal crystals by random potentials.

Structural defects are ubiquitous in condensed matter, and not always a nuisance. For example, they underlie phenomena such as Anderson localization and hyperuniformity, and they are now being exploited to engineer novel materials. Here, we show experimentally that the density of structural defects in a 2D binary colloidal crystal can be engineered with a random potential.

Clustering of Janus particles in an optical potential driven by hydrodynamic fluxes.

Self-organisation is driven by the interactions between the individual components of a system mediated by the environment, and is one of the most important strategies used by many biological systems to develop complex and functional structures. Furthermore, biologically-inspired self-organisation offers opportunities to develop the next generation of materials and devices for electronics, photonics and nanotechnology. In this work, we demonstrate experimentally that a system of Janus particles (silica microspheres half-coated with gold) aggregates into clusters in the presence of a Gaussian optical potential and disaggregates when the optical potential is switched off.

Electro- and photosensitive azopolymer for alignment of liquid crystals.

We report an electro- and photosensitive metal containing polymer material for alignment of liquid crystals (LCs). Irradiation with polarized light and/or application of dc-field result in an anisotropy of the polymer and formation of an easy orientation axes of a LC on the polymer surface. The light-induced anisotropy of the polymer and the LC anchoring on the polymer surface can be controlled by the low dc-field at room temperature.

Formation of liquid-crystal cholesteric pitch in the centimeter range.

The formation of a macroscopic cholesteric spiral in a nematic liquid crystal (LC) doped with chiral molecules is studied. Measurements of the orientation of the disclination line formed in a LC θ-cell manufactured with one substrate having linear in-plane alignment and the opposing substrate having circular alignment showed the formation of a uniform macroscopic cholesteric spiral with a pitch length of centimeters. We found a linear dependence of the reciprocal pitch p(-1) on the concentration c in a wide range of p, extending from micrometers up to several centimeters.