Hypersonic properties of nematic and smectic polymer liquid crystals

Journal Article · Thu Mar 31 23:00:00 EST 1988 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.37.2637· OSTI ID:5310971

Krueger, J K; Pee-dieresistz, L; Siems, R; Unruh, H; Eich, M; Herrmann-Schoenherr, O; Wendorff, J H

We have investigated the elastic and the optical properties of nematic and smectic side chain polymer liquid crystals at hypersonic frequencies. In contrast to classical liquid crystals, the polymer materials show a significant coupling between the static order parameter and the square of the elastic strain epsilon/sub 3/. The inverse shear stiffness constants do not diverge. All elastic constants behave continuously at the nematic-isotropic transition (T/sub n//sub i/). From certain optoacoustic properties and the refractive index functions, it follows that order-parameter fluctuations play no role at T/sub n//sub i/, but that the glass transition dominates the dynamic elastic properties at hypersonic frequencies.

• Research Organization: Fachbereich Physik, Universitaet des Saarlandes, D-6600, Saarbruecken, Federal Republic of Germany
• OSTI ID: 5310971
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 37:7; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
BRILLOUIN EFFECT
COHERENT SCATTERING
CRYSTALS
ELASTICITY
FLUIDS
INFRARED SPECTROMETERS
LIQUID CRYSTALS
LIQUIDS
MEASURING INSTRUMENTS
MEASURING METHODS
MECHANICAL PROPERTIES
OPTICAL PROPERTIES
PHOTOACOUSTIC SPECTROMETERS
PHYSICAL PROPERTIES
POLARIZATION
POLYMERS
REFRACTIVITY
SCATTERING
SOUND WAVES
SPECTROMETERS
TENSILE PROPERTIES
ULTRASONIC WAVES
VELOCITY