Bending nematic liquid crystal membranes with phospholipids

Area of Science:

• Physics and Chemistry of Materials
• Biosensor Technology
• Liquid Crystal Science

Background:

• Phospholipid interactions with liquid crystals (LCs) are crucial for biosensor development.
• High concentrations of 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) can alter LC director alignment at interfaces.
• Previous studies observed unexpected brightening of LC textures at very high DLPC concentrations.

Purpose of the Study:

• To investigate the physical mechanism behind the brightening of LC textures at high DLPC concentrations.
• To confirm the proposed interface bending phenomenon.
• To explore the sensitivity of the bent interface to environmental stimuli.

Main Methods:

• Optical surface profiler measurements were used to analyze the interface shape.
• Liquid crystal films of 4-cyano-4'-octylbiphenyl (8CB) were studied.
• The response to air pressure variations and acoustic stimulation was measured.

Main Results:

• Optical surface profiler measurements confirmed that the 8CB liquid crystal interface bends towards the lipid-coated side at high DLPC concentrations.
• The bent interface demonstrated extreme sensitivity to air pressure variations.
• Acoustic stimulation of the bent interface produced a measurable optical response.

Conclusions:

• The observed interface bending provides a physical explanation for the brightening of LC textures at high DLPC concentrations.
• The high sensitivity of the bent interface to pressure variations suggests potential for novel sensor applications.
• Further research into the underlying physical mechanism is warranted.