Self-assembled ultrathin (5-15 nm) films of carbosilane dendrimers wit
h mesogenic units on the periphery, obtained after deposition on mica
surfaces, have been studied with atomic force microscopy. Dendritic po
lymers with 12, 36, and 108 mesogenic cholesteryl end groups, first, s
econd, and third generation, respectively, were employed. Solvent cast
ing was used to generate the films. At high concentrations of the dend
rimers in solution, flat, homogeneous films of 2-4 dendrimer layers we
re found. For low dendrimer concentrations, a single dendrimer monolay
er exhibiting an irregular cellular pattern of holes was observed. The
thickness of the monolayer correlated well with the diameter of the d
endrimers and with wide-angle X-ray scattering results obtained on cry
stalline powders. Annealing of the films of G1 and G2 in the liquid cr
ystalline phase caused reorientation of the molecules at the surface.
The third-generation dendrimer with 108 end groups (G3), the periphery
of which is densely packed with mesogens, behaved differently and did
not show dewetting or reorientation upon annealing, which is attribut
ed to lower molecular mobility.