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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
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Electric-field-induced phase transitions in bent-core mesogens determined by x-ray diffraction
J Ortega1, C L Folcia, J Etxebarria
1Física Aplicada II, FCT/ZFT, UPV/EHU, Apartado 644, E-48080 Bilbao, Spain. josu.ortega@ehu.es
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 21, 2011
Summary
Electric fields alter x-ray diffraction in bent-core liquid crystals. Columnar B1 phases switch to smectic C polar phases, while dark conglomerate structures show increased order and spacing under electric fields.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Crystallography
Background:
- Bent-core liquid crystals exhibit unique mesophases.
- Electric field responses are crucial for device applications.
- X-ray diffraction is a key technique for structural analysis.
Purpose of the Study:
- Investigate electric field effects on bent-core liquid crystal structures.
- Characterize phase transitions and structural changes using x-ray diffraction.
- Understand the influence of electric fields on columnar B1 and dark conglomerate phases.
Main Methods:
- X-ray diffraction analysis of four bent-core liquid crystal compounds.
- Application of external electric fields to induce structural changes.
- Comparison of diffraction patterns in the absence and presence of electric fields.
Main Results:
- Columnar B1 phases transition to smectic C polar (SmCP) phases under electric fields.
- Dark conglomerate (DC) structures show unaltered Bragg reflection positions but increased correlation length in one compound.
- A slight enhancement of smectic spacing was observed in DC phases with applied fields.
Conclusions:
- Electric fields can induce significant structural reorientations in bent-core liquid crystals.
- The observed phase transitions and structural modifications are dependent on the specific mesophase.
- These findings provide insights into the electro-structural coupling in complex liquid crystalline materials.
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