We have studied the time-dependent behavior of the director following the step-rotation of a nematic sample subject to a static magnetic field. The director orientation has been monitored using ESR spectroscopy, and we have developed a model-independent analysis of the spectra to yield the distribution function for the director with respect to the magnetic field. This reveals that immediately following the step-rotation the director is uniformly aligned parallel to the field and then adopts a range of orientations before returning to a state of uniform alignment with the director at the step-rotation angle to the field. This unusual behavior of the director is compared with the predictions of nematodynamic theory by employing an exact treatment of the Leslie-Ericksen equations to calculate the time and space dependence of the director orientation.
A novel magnetohydrodynamic experiment: Step-rotation of a nematic subject to a magnetic field
ORIAN, LAURA;POLIMENO, ANTONINO
2000
Abstract
We have studied the time-dependent behavior of the director following the step-rotation of a nematic sample subject to a static magnetic field. The director orientation has been monitored using ESR spectroscopy, and we have developed a model-independent analysis of the spectra to yield the distribution function for the director with respect to the magnetic field. This reveals that immediately following the step-rotation the director is uniformly aligned parallel to the field and then adopts a range of orientations before returning to a state of uniform alignment with the director at the step-rotation angle to the field. This unusual behavior of the director is compared with the predictions of nematodynamic theory by employing an exact treatment of the Leslie-Ericksen equations to calculate the time and space dependence of the director orientation.
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