Lateral and normal forces between patterned substrates induced by nematic fluctuations.

Area of Science:

• Soft Matter Physics
• Materials Science
• Condensed Matter Physics

Background:

• Nematic liquid crystals exhibit unique properties due to director fluctuations.
• Confining liquid crystals between patterned substrates introduces complex interactions.

Purpose of the Study:

• Investigate fluctuation-induced forces between periodically patterned substrates in nematic liquid crystals.
• Compare these forces with van der Waals forces.

Main Methods:

• Gaussian approximation applied to nematic director thermal fluctuations.
• Analysis of effective forces in a confined liquid crystal system.

Main Results:

• Discovered an oscillating shear force dependent on lateral pattern shift.
• Identified normal forces as either repulsive or attractive based on parameters.
• Quantified fluctuation-induced lateral forces relative to van der Waals forces.

Conclusions:

• Thermal fluctuations significantly contribute to lateral forces in patterned liquid crystal systems.
• The observed forces can be tuned by substrate patterning and material parameters.
• Potential for designing novel actuators and sensors based on these forces.