Atomic force microscope evidence for the existence of smecticlike surface layers in the isotropic phase of a nematic liquid crystal
Using a temperature controlled atomic force microscope we have observed presmectic layering in the isotropic phase of 4-cyano-4(')-n-octylbiphenyl (8CB) on silanated glass. The first molecular layer shows a smecticlike compressibility modulus of B approximately 10(7) N/m(2) and is stable more than 20 K beyond the bulk clearing point. It is followed by a presmectic modulation that increases when cooling towards the isotropic-nematic transition. In the bulk isotropic phase, the layers cover approximately 70% of the glass surface, indicating a clusterlike organization.
Kocevar
K
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
Blinc
R
Musevic
I