Design rules for 2D field mediated assembly of different shaped colloids into diverse microstructures

Area of Science:

• Materials Science
• Soft Matter Physics
• Colloidal Science

Background:

• Assembling diverse particle shapes into ordered microstructures is crucial for advanced materials.
• Controlling particle assembly with external fields remains a significant challenge.

Purpose of the Study:

• To investigate the assembly of different shaped colloidal particles into ordered microstructures using 2D AC electric fields.
• To understand how particle shape and AC electric fields influence microstructural formation.

Main Methods:

• Utilized 2D AC electric fields to mediate the assembly of disk, ellipse, square, and rectangle shaped colloidal particles.
• Employed particle tracking and order parameter computation to analyze microstructural states.
• Validated experimental findings with computer simulations.

Main Results:

• Successfully assembled amorphous, liquid crystalline (nematic, smectic, tetratic), and crystalline microstructures.
• Demonstrated that particle shape (anisotropy, corner curvature) and AC field conditions dictate the resulting microstructures.
• Showcased how dipolar interactions, alongside particle packing, drive structure formation, enabling assembly of hard particle phases and additional novel structures.

Conclusions:

• AC electric field mediated assembly provides design rules for creating diverse microstructures from various particle shapes.
• This approach offers scalable and reconfigurable routes for particle-based materials, displays, and printing technologies.