Structural transformations in tetravalent nematic shells induced by a magnetic field

Area of Science:

• Soft Matter Physics
• Materials Science
• Liquid Crystal Science

Background:

• Theoretical studies have explored applied fields' effects on liquid crystal shells, suggesting methods for defect control.
• Experimental validation of these theoretical predictions for liquid crystal shell structures remains limited.

Purpose of the Study:

• To experimentally and computationally investigate structural transformations in tetravalent nematic liquid crystal shells under a uniform magnetic field.
• To understand defect migration and structural evolution in both homogeneous and inhomogeneous shell geometries.

Main Methods:

• Utilized experimental techniques and simulations to study liquid crystal shell structural changes.
• Analyzed defect trajectories and dynamics influenced by curvature walls.
• Developed a predictive rule based on the angle between magnetic field projection (Bs) and defect orientation (n+½).

Main Results:

• Observed evolution of initial defect structures into bipolar configurations with defects migrating to poles.
• Identified curvature walls controlling defect movement and dynamics.
• Established a symmetry-based rule correlating Bs and n+½ angles with defect trajectories and inversion wall shapes.
• Reported the first observation of a hybrid splay-bend Helfrich wall in inhomogeneous shells.

Conclusions:

• The study provides a predictive framework for controlling liquid crystal shell structures via magnetic fields.
• The findings bridge theoretical predictions and experimental observations in liquid crystal shell physics.
• Demonstrated controlled induction of complex structural transformations and observed novel phenomena like hybrid Helfrich walls.