Flow and viscosity studies in nematic liquid crystals

Flow and viscosity studies in nematic liquid crystals 

Originally, the basic idea was realized without an FC switch by a continuous or one-tum rotation of the sample perpendicular to the external magnetic field direction, in order to induce a flow but such a mechanical rotation is, similar to a mechanical FC switch, much too slow to establish reproducible states of motions in common, low-viscosity anisotropic liquids such measurements were therefore restricted to high-viscosity liquid crystalline polymers. Fast electronic FC eliminates these restrictions, but to date the new tedmique has only been used with proton spin signals owing to instrumental limitations.  

In the simple case where the sample material contains only one type of proton spin pair with a separation ri2 and a fixed (i.e. over the time of the measurement not motionaUy averaged) orientation Bi2 relative to the external detection field B, the spectrum consists of two lines (Fake doublet) with splitting A  

In a pioneering viscosity study of polymeric (high-viscosity) liquid crystals Martins et al. considered an extension of eqiudon (9a), a planar LesAe-Ericksen approximation for director motions in a plane (jc, z) with an elastic inhomogeneity term periodic in one dimension (z). This approach. 

Frequency-dependent dipolar relaxation In ordered i stems 

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