Flexoelectric polarization in hybrid nematic films

Area of Science:

• Materials Science
• Condensed Matter Physics

Background:

• Flexoelectricity in liquid crystals is a key phenomenon for device applications.
• Understanding director reorientation in hybrid films is crucial for advanced materials.

Purpose of the Study:

• To investigate the behavior of penthylcyanobiphenyl (5CB) liquid crystal films on glycerol under an in-plane electric field.
• To determine the electric field and film thickness dependence of 2pi reorientations (2pi walls).
• To interpret these findings using continuum elastic theory and calculate flexoelectric coefficients.

Main Methods:

• Fabrication of hybrid films of 5CB on glycerol.
• Application of an in-plane electric field to induce flexoelectric polarization.
• Measurement of the width of 2pi reorientations (2pi walls) as a function of electric field and film thickness.
• Analysis using continuum elastic theory.

Main Results:

• Observed electric field and film thickness dependence of 2pi reorientation widths.
• The study successfully trapped director reorientations using the applied electric field.
• The difference between flexoelectric coefficients e(1) and e(3) was determined to be +11 pC/m.

Conclusions:

• The study provides quantitative insights into flexoelectric phenomena in hybrid liquid crystal films.
• The findings validate the application of continuum elastic theory for describing these systems.
• The determined flexoelectric coefficients are valuable for the design of novel electro-optic devices.