Molecular Structure of Canonical Liquid Crystal Interfaces.
Numerous applications of liquid crystals rely on control of molecular orientation at an interface. However, little is known about the precise molecular structure of such interfaces. In this work, synchrotron X-ray reflectivity measurements, accompanied by large-scale atomistic molecular dynamics simulations, are used for the first time to reconstruct the air-liquid crystal interface of a nematic material, namely, 4-pentyl-4'-cyanobiphenyl (5CB). The results are compared to those for 4-octyl-4'-cyanobiphenyl (8CB) which, in addition to adopting isotropic and nematic states, can also form a smectic phase. Our findings indicate that the air interface imprints a highly ordered structure into the material; such a local structure then propagates well into the bulk of the liquid crystal, particularly for nematic and smectic phases.
Argonne National Laboratory , Argonne, Illinois 60439, United States.
Monirosadat
M
Sadati
Hadi
H
Ramezani-Dakhel
Wei
0000-0002-9996-3733
W
Bu
Emre
E
Sevgen
Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
Zhu
Z
Liang
Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
Cem
C
Erol
Mohammad
M
Rahimi
Argonne National Laboratory , Argonne, Illinois 60439, United States.
Nader
N
Taheri Qazvini
Binhua
0000-0001-5932-4905
B
Lin
Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
Nicholas L
NL
Abbott
Benoı T
BT
Roux
Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
Mark L
ML
Schlossman
Argonne National Laboratory , Argonne, Illinois 60439, United States.
Juan J
0000-0002-3526-516X
JJ
de Pablo