An atomic force microscope was used to write planar alignment patterns on a polyimide-coated glass substrate. Paired with a substrate treated for homeotropic alignment, the resulting hybrid liquid crystal cell produced fixed gray scale images with pixel sizes of order 1 m. The physics and efficacy of this architecture are compared to a cell having planar alignment at both substrates.

Rubbed polyimide surfaces, which are used for liquid crystal alignment, generally exhibit microscopic grooves which lie parallel to the rubbing direction. Using atomic force microscopy we examined both the grooves and the fibers that create the grooves. We find that for a wide range of rubbing strengths, the microstructure of the grooves, as determined by their radii of curvature, correlates well with the microscopic topography of the fibers. This result indicates that the rubbing-induced topography depends on not only the characteristic rubbing strength, but on the structure of the rubbing fiber as well.

We have used atomistic molecular-dynamics simulations to model the detailed molecular configuration of 5CB (4-n-pentyl-4'-cyanobiphenyl) molecules in the form of a nanoscopic liquid crystal droplet in a vacuum microgravity environment. We find the equilibrium state of droplets consisting of as few as 26 or 50 molecules to exhibit significant nematic ordering. The shape of the droplets is also anisotropic, but there is little angular correlation between the nematic director and the long axis of the droplet. Some tendency to micelle formation is observed in droplets of 50 molecules.

A polyimide film that was spin coated onto a glass substrate was multiply rubbed along different directions and studied using ellipsometry and atomic force microscopy. The data show a minimum required rubbing strength for the onset of orientational order in the polyimide. When over rubbed along an axis perpendicular to the first rubbing direction, a smaller rubbing strength was required for the onset of order along this direction. This behavior indicates that the polyimide had been partially disentangled by the initial rubbing, needing only weaker rubbing to be reoriented by the second rubbing.

Magnetic levitation was used to stabilize cylindrical columns of a paramagnetic liquid in air between two solid supports.The maximum achievable length to diameter ratio R_,× was -(3.10 ± 0.07), very close to the Rayleigh-Plateau limit of_. For smaller R, the stability of the column was measured as a function of the Bond number, which could be continuously varied by adjusting the strength of the magnetic field.