Pattern formation in confined colloidal liquid crystals*

We report on the confinement of colloidal liquid crystals in three dimensional chambers, where the confinement lengthscale is comparable to the length of the rods. We present results for both virus particles and silica rods, where in the latter case we exploit silica's large density difference with respect to the dispersing solvent to study isotropic, nematic and smectic phases confined into a single chamber. Combining laser scanning confocal microscopy and soft-lithography techniques enables us to characterize the configurations down to the single particle level. We compare to simulations and theory. Finally, by modifying the silica rods we are able to produce novel low-density colloidal liquid crystals with anti-nematic order. This shows how colloidal liquid crystals can both shine light on more traditional liquid crystal problems and enable us to design novel tunable liquid crystalline phases.