A new experimental method is presented which is a useful approach in studying the reorientational dynanics in liquid crystals by means of dielectric measurements at microwave frequencies. The theoretical model is developed to describe the motion of the director when it is driven by two orthogonal electric or magnetic fields. A specific set up for the experimental apparatus is described. Experiments in fairly good agreement with the theoretical model are given for a nematic mesophase at different temperatures and field values. The capabilities of the method in monitoring the slow reorientatinal properties of collective molecular motions in liquid crystals are demonstrated. Possible refinements of the experimental apparatus to allow more quantitative measurements of the different physical parameters of anisotropic media are indicated.
Director Reorientation In Nematics Studied By Microwave Dielectrometry
GAMMAITONI, Luca;
1991
Abstract
A new experimental method is presented which is a useful approach in studying the reorientational dynanics in liquid crystals by means of dielectric measurements at microwave frequencies. The theoretical model is developed to describe the motion of the director when it is driven by two orthogonal electric or magnetic fields. A specific set up for the experimental apparatus is described. Experiments in fairly good agreement with the theoretical model are given for a nematic mesophase at different temperatures and field values. The capabilities of the method in monitoring the slow reorientatinal properties of collective molecular motions in liquid crystals are demonstrated. Possible refinements of the experimental apparatus to allow more quantitative measurements of the different physical parameters of anisotropic media are indicated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
