Helical Columnar Liquid Crystal Exhibiting Both Polarization Retention and Ferroelectric Switching at Room...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Organic Chemistry

Background:

• Ferroelectric columnar liquid crystals (FCLCs) are explored for high-density ferroelectric random-access memory (FeRAM).
• Achieving uniform polarization and ferroelectric switching in FCLCs at room temperature (RT) remains a significant challenge.

Purpose of the Study:

• To design and synthesize novel C3-symmetric star-shaped mesogens for RT-operable FCLCs.
• To investigate the self-assembly and ferroelectric switching properties of synthesized liquid crystals.

Main Methods:

• Synthesis of two C3-symmetric star-shaped mesogens with different polar linkers (1,2,3-triazole and amide).
• Characterization of liquid crystal phases and structural transitions using appropriate techniques.
• Evaluation of ferroelectric switching behavior and dielectric properties at room temperature.

Main Results:

• One synthesized FCLC with a 1,2,3-triazole linker exhibited ferroelectric switching operable down to RT, retaining axial macrodipole.
• This FCLC showed a transition from helical to nonhelical columnar phase upon heating.
• The other FCLC with an amide linker displayed only paraelectric behavior in a nonhelical columnar phase.

Conclusions:

• The mesogen design incorporating a bulky 1,2,3-triazole linker is crucial for achieving RT ferroelectric columnar liquid crystal behavior.
• The size of the polar unit significantly influences self-assembly and dielectric properties.
• This RT-operable FCLC holds potential for developing high-density FeRAM devices.