Accession Number : AD0848719

Title :   Physical Properties of the Cholesteric Mesophase.

Descriptive Note : Interim rept. no. 3, 10 May 67-10 May 68,

Corporate Author : KENT STATE UNIV OH LIQUID CRYSTAL INST

Personal Author(s) : Brown, Glenn H.

Report Date : 26 JUN 1968

Pagination or Media Count : 44

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)

Descriptors :   *CRYSTALS), (*CHOLESTERYL ESTERS, PHYSICAL PROPERTIES), (*ULTRASONIC RADIATION, CHOLESTERYL ESTERS), (*LIQUIDS, MECHANICAL WAVES, QUARTZ, REFLECTION, COMPUTER PROGRAMMING, X RAY DIFFRACTION.

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE