Entropic Locking Stabilized Macroscopic Ferromagnetic Phase in Colloidal Chiral Liquid Crystals.

Area of Science:

• Materials Science
• Soft Matter Physics
• Nanotechnology

Background:

• Ferronematics, materials with controllable magnetic phases, were proposed decades ago but not realized in chiral liquid crystals.
• Existing ferronematic materials are limited in their applications and fabrication methods.

Purpose of the Study:

• To develop a lyotropic ferromagnetic chiral nematic liquid crystal.
• To enable the formation of macroscopic chiral monodomains using weak magnetic fields.
• To explore applications in photonics, actuators, sensors, and intelligent soft matter.

Main Methods:

• Homogeneously dispersing anisotropic barium hexaferrite nanoplates into a cellulose nanocrystal matrix.
• Utilizing weak magnetic fields (approximately 50 mT) for domain alignment and coarsening.
• Investigating the interaction between nanoplates and the chiral director.

Main Results:

• Successfully created a lyotropic ferromagnetic chiral nematic liquid crystal.
• Achieved formation of a macroscopic chiral monodomain responsive to weak magnetic fields.
• Demonstrated that nanoplates align with the chiral director, guiding domain formation and imparting ferromagnetism.

Conclusions:

• This work presents a scalable platform for low-field fabrication of ferromagnetic chiral nematic liquid crystal monodomains.
• The developed material offers a new avenue for creating responsive soft matter with diverse applications.
• The findings pave the way for advancements in photonics, soft actuators, sensors, and radiative cooling materials.