Dynamics of 8CB confined into porous silicon probed by incoherent neutron backscattering experiments.

Régis Guégan (1) , Ronan Lefort (1) , Wilfried Béziel (1) , Denis Morineau (1) , Mohammed Guendouz (2) , Bernhard Frick (3)

1 GMCM - Groupe matière condensée et matériaux
2 FOTON - Fonctions Optiques pour les Technologies de l'informatiON
3 ILL - Institut Laue-Langevin

Confinement in the nanochannels of porous silicon strongly affects the phase behavior of the archetype liquid-crystal 4-n-octyl-4-cyanobiphenyl (8CB). A very striking phenom- enon is the development of a short-range smectic order, which occurs on a very broad temperature range. It suggests in this case that quenched disorder effects add to usual finite size and surface interaction effects. We have monitored the temperature variation of the molecular dynamics of the confined fluid by incoherent quasielastic neutron scat- tering. A strongly reduced mobility is observed at the highest temperatures in the liquid phase, which suggests that the interfacial molecular dynamics is strongly hindered. A continuously increasing slowdown appears on cooling together with a progressive growth of the static correlation length

Domaines: Matière Molle [cond-mat.soft]

Régis Guégan, Ronan Lefort, Wilfried Béziel, Denis Morineau, Mohammed Guendouz, et al.. Dynamics of 8CB confined into porous silicon probed by incoherent neutron backscattering experiments.. 3rd International Workshop on Dynamics in Confinement, Mar 2006, Grenoble, France. pp.29-34, ⟨10.1140/epjst/e2007-00011-5⟩. ⟨hal-00022838⟩