Atomic force microscopy study of structural organization of carbosilane liquid crystalline dendrimer

Structural organization of a carbosilane liquid crystalline dendrimer of fi fth generation with cyanobiphenyl mesogenic groups in the 25-130 degrees C range was examined by atomic force microscopy(AFM) Studies were performed o n the dendrimer films of different thicknesses, from single macromolecular layers to films several micrometers thick. Packing motifs of spherical macr omolecules (5.5 nm in diameter) were revealed in submicrometer AFM images o f the dendrimer films. Rectangular and hexagonal lattices were found in the single layers on different substrates. With an increase of film thickness, first smectic layers are formed, and then domains consisting of aggregates of flat-on lying and edge-on standing smectic layers were found. In thick films, the domains exhibit layered structures of different thicknesses and with different orientations. AFM images recorded at different temperatures demonstrated height changes of different domains caused by anisotropic chan ges of lattices of the smectic layers.