How smectic-A and smectic-C liquid crystals resolve confinement-induced frustration in spherical shells

Area of Science:

• Soft matter physics
• Liquid crystal phases
• Materials science

Background:

• Smectic liquid crystals possess layered structures that face challenges when confined within spherical shells.
• Smectic-A (SmA) phases exhibit frustration due to radial layer constraints, leading to complex textures like spherical lunes and twist deformations.
• The smectic-C (SmC) phase, with its non-zero tilt angle, offers potential for different frustration resolution mechanisms under confinement.

Purpose of the Study:

• To investigate the response of smectic-C liquid crystals to tangential shell confinement.
• To experimentally and theoretically analyze the structural changes in SmC phases within spherical shells compared to SmA phases.
• To understand how the tilt angle in SmC phases influences frustration resolution.

Main Methods:

• Experimental observation of liquid crystal phases within spherical shells.
• Theoretical modeling to analyze the behavior of smectic phases under confinement.
• Analysis of structural parameters such as domain width, layer modulation, and twist deformations.

Main Results:

• Smectic-C phases in spherical shells show twice as wide and half as many lunes compared to SmA phases.
• The secondary herringbone-like modulation is lost in the SmC phase.
• A configuration with no layer twist but uniform layer bend is adopted when the tilt angle (τ) is sufficiently large.

Conclusions:

• Smectic-C phases effectively resolve frustration in spherical confinement through structural reorganization.
• The tilt angle in SmC phases plays a crucial role in dictating the final configuration.
• This research enhances understanding of smectic behavior in curved geometries and opens avenues for exploring related soft matter phases.