Flexoelectricity of a Calamitic Liquid Crystal Elastomer Swollen with a Bent-core Liquid Crystal

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of Materials Chemistry

DOI:https://doi.org/10.1039/b911652d· OSTI ID:1020065

Chambers, M; Verduzco, R; Gleeson, J; Sprunt, S; Jakli, A

We have measured the electric current induced by mechanical distortion of a calamitic liquid crystal elastomer (LCE) swollen with a low molecular weight bent-core nematic (BCN) liquid crystal, and have determined, for the first time, the bend flexoelectric coefficient e{sub 3} of such a BCN-LCE composite. In one method, we utilize air-pressure to induce a mechanical bend deformation and flexoelectric polarization in a BCN-LCE film, and then measure the polarization current as a function of time. An alternative technique uses a rotary-motor driven scotch yoke to periodically flex the BCN-LCE; in this case, the magnitude and phase of the induced current are recorded via a lock-in amplifier. The flexoelectric coefficient, e{sub 3}, was found to be {approx}20 nC/cm{sup 2}, and is stable in magnitude from room temperature to {approx}65 C. It is about one third the value measured in samples of the pure BCN; this fraction corresponds closely to the molar concentration of BCN in the LCE. The flexoelectric current increases linearly with the magnitude of the bend deformation and decays with frequency. These observations indicate a promising way forward towards producing very low-cost, self-standing, rugged electromechanical energy conversion devices.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1020065
• Report Number(s): BNL--95913-2011-JA
• Journal Information: Journal of Materials Chemistry, Journal Name: Journal of Materials Chemistry Journal Issue: 42 Vol. 19; ISSN JMACEP; ISSN 0959-9428
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
DEFORMATION
ELASTOMERS
ELECTRIC CURRENTS
ENERGY CONVERSION
LIQUID CRYSTALS
LOCK-IN AMPLIFIERS
MOLECULAR WEIGHT
POLARIZATION
national synchrotron light source