Alignment and phase transition induced by surface action in lyotropic nematic liquid crystals

Area of Science:

• Materials Science
• Physical Chemistry
• Soft Matter Physics

Background:

• Lyotropic nematic liquid crystals (LNLC) exhibit unique alignment behaviors.
• Surface interactions play a critical role in controlling the properties of liquid crystals.
• Understanding boundary effects is crucial for designing advanced liquid crystal devices.

Purpose of the Study:

• To investigate the influence of treated substrates on the alignment properties of lyotropic nematic liquid crystals.
• To explore the impact of surface hydrophobicity/hydrophilicity and rubbing on LNLC alignment.
• To study surface-induced phase transitions and director dynamics in confined LNLC.

Main Methods:

• Utilized treated substrates with varying surface properties (hydrophobic, hydrophilic, rubbed, nonrubbed).
• Examined LNLC alignment under different confinement conditions.
• Observed reorientation and relaxation processes of the nematic director.
• Analyzed characteristic times of dynamic processes.

Main Results:

• LNLC particles follow surface anchoring direction only under strong confinement.
• Surface action induced a phase transition in strongly confined LNLC.
• Reorientation and relaxation times depend on sample thickness and surface properties.

Conclusions:

• Surface properties significantly dictate LNLC alignment, particularly in confined geometries.
• Strong confinement enables surface-induced phase transitions and influences director dynamics.
• Tailoring surface treatments is key to controlling LNLC behavior for specific applications.