https://doi.org/10.1140/epje/i2003-10013-y
Structure and polarity of 8CB films evaporated onto solid substrates
1
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI 1000, Ljubljana, Slovenia
2
J. Stefan Institute, Jamova 39, SI 1000, Ljubljana, Slovenia
3
Research Institute for Materials, University of Nijmegen, Toernooiveld 1, 6525 ED, Nijmegen, The Netherlands
* e-mail: irena.drevensek@ijs.si
Received:
27
January
2003
Revised:
6
May
2003
Published online: 25 June 2003
Brewster-angle reflection ellipsometry and surface optical second harmonic generation were used to study the growth of 4'-n-octyl-4-cyanobiphenyl (8CB) films evaporated in air onto polymeric and quartz glass substrates. The layer-by-layer growth of the films terminates after formation of two distinctive interfacial layers. Both of these two layers are polar and tilted. In the first layer the molecules lie nearly flat on the surface, while in the second layer they point on average about 50° toward the surface normal. The dipole moment of the second layer has a lower magnitude and an opposite direction with respect to the dipole moment of the first layer.
PACS: 61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions – / 68.03.Fg Evaporation and condensation – / 42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation –
© EDP Sciences, Springer-Verlag, Società Italiana di Fisica, 2003
