Polymer, Vol.38, No.12, 3069-3083, 1997
Macroscopic Structures in Liquid-Crystal Systems Prepared with Spin-Coating
Macroscopic structures have been created in poly(gamma-benzyl-L-glutamate) films, OM-20 films, poly(hexyl-isocyanate) films and 4’-pentyl-4-cyanobiphenyl using spin-coating equipment with rotating cap. The orientation of the molecules in the films has been determined using crossed polarizers. The visible macroscopic maltese crosses were the result of a radial symmetrical orientation of the molecules in the film plane. The development of the macroscopic structures during the spin coating process has been studied. The late development of the structures at low flow velocity explain the none appearance of Coriolis effects on the structure. An asymmetrical growth of the structure in the film plane has been observed during the spin-coating process independent of the polymer used. The experimental results led to a theoretical model of a flow-induced spherulite growth.