Physical Properties of the Cholesteric Mesophase.
Abstract
This report outlines research on the properties of ultrasonic waves (11 MHz, 14.5 MHz and 30 MHz) in a cholesteric liquid crystal. The method involves the measurement of the complex reflection coefficient that occurs when a transverse mechanical wave reflects from the boundary of a fused quartz substrate and a liquid crystal. Another measurement involves phase-coherent detection as a means of measuring phase-shift using ultrasonic shear waves. The reflection coefficient is quite sensitive to the liquid crystalline state. There is a large change in the reflection coefficient (r) at the nematic-isotropic point but its dependence on temperature is not always the same at different frequencies. At some frequencies plots of r as a function of temperature show an increase in r as the temperature rises while at other frequencies r decreases. Phase-shift measurements in cholesteryl nonanoate show only a few degrees shift which is characteristic of most liquids. Values for skin depth and velocity of ultrasonic waves in cholesteryl nonanoate were established. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 26, 1968
- Accession Number
- AD0848719
Entities
People
- Glenn H. Brown
Organizations
- Kent State University