Synthesis, assembly, and image analysis of spheroidal patchy particles

Area of Science:

• Materials Science
• Colloid Science
• Nanotechnology

Background:

• Anisotropic particles with controlled shape and surface interactions are crucial for advanced material design.
• Understanding self-assembly mechanisms is key to developing novel functional materials.

Purpose of the Study:

• To develop a method for synthesizing and imaging Janus spheroid and kayak-shaped patchy particles.
• To investigate the self-assembly behavior of these particles influenced by shape and patch interactions.
• To characterize the role of selective gold-to-gold bonding in assembly structures.

Main Methods:

• Fabrication of Janus particles via sequential chrome/gold deposition and uniaxial deformation.
• Imaging using combined reflection and fluorescence confocal microscopy.
• Development of image analysis algorithms to determine patch orientation.
• Characterization of self-assembly at varying salt concentrations.

Main Results:

• Successful synthesis and imaging of Janus spheroid and kayak particles with shape and interaction anisotropy.
• Demonstration of selective gold-to-gold patch bonding at intermediate salt concentrations.
• Observation of gel-like structures with nonselective bonding at higher salt concentrations.
• Correlation between orientational order, selective bonding, and particle shape anisotropy in self-assembled structures.

Conclusions:

• The developed method enables precise control over particle shape and surface functionalization.
• Particle shape anisotropy and selective patch interactions significantly influence self-assembly.
• These findings provide insights into designing complex structures from anisotropic building blocks.