Anomalous Increase in Nematic-Isotropic Transition Temperature in Dimer Molecules Induced by a Magnetic Field.
We have determined the nematic-isotropic transition temperature as a function of an applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flexible spacers with odd numbers of methylene groups. They show an unprecedented magnetic field enhancement of nematic order in that the transition temperature is increased by up to 15 K when subjected to a 22 T magnetic field. The increase is conjectured to be caused by a magnetic-field-induced decrease of the average bend angle in the aliphatic spacers connecting the rigid mesogenic units of the dimers.
Chemical Physics Interdisciplinary Program & Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA.
S M
SM
Salili
Department of Nonlinear Phenomena, Institute for Experimental Physics, Otto von Guericke University Magdeburg, Magdeburg 39106, Germany.
M G
MG
Tamba
Department of Physics, Kent State University, Kent, Ohio 44242, USA.
S N
SN
Sprunt
Department of Chemistry, University of Hull, Hull HU6 7RX, United Kingdom.
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C
Welch
Department of Chemistry, University of Hull, Hull HU6 7RX, United Kingdom.
G H
GH
Mehl
Chemical Physics Interdisciplinary Program & Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA.
A
A
Jákli
Department of Physics, Kent State University, Kent, Ohio 44242, USA.
J T
JT
Gleeson