Investigating room temperature ferroelectric nematogens and their structure-property relationships

Area of Science:

• Materials Science
• Condensed Matter Physics
• Organic Chemistry

Background:

• Ferroelectricity in low molar mass liquid crystals is a recent discovery.
• Identifying room-temperature ferroelectric materials is crucial for technological applications.

Purpose of the Study:

• To synthesize and characterize new ferroelectric nematogens based on the RM734 template.
• To investigate structure-property relationships for the ferroelectric nematic phase.

Main Methods:

• Systematic modification of molecular structure by altering terminal groups, lateral chain position and number, fluorination, and chain length.
• Characterization of phase transitions and ferroelectric properties.

Main Results:

• 70 ferroelectric nematogen compounds were synthesized, all exhibiting the ferroelectric nematic phase.
• 19 compounds showed transitions to the ferroelectric nematic phase below 30°C, a significant increase in room-temperature candidates.
• Most compounds exhibited monotropic N_F-I transitions but could be supercooled to room temperature with good stability.

Conclusions:

• Molecular design allows tuning of phase stability and viscosity, controlling switching speed and polarization retention.
• Understanding structure-property relationships advances the development of enantiotropic room-temperature ferroelectric liquid crystals for devices.