Capillary Assembly of Anisotropic Particles at Cylindrical Fluid-Fluid Interfaces

Area of Science:

• Colloid and surface science
• Materials engineering
• Computational physics

Background:

• Colloidal particles at liquid interfaces offer unique assembly opportunities.
• Interfacial curvature can direct colloidal self-assembly alongside particle properties.

Purpose of the Study:

• To investigate the self-assembly of rod-shaped particles at a curved fluid-fluid interface.
• To explore how interfacial curvature and particle properties influence colloidal assembly.

Main Methods:

• Utilized the finite element method (Surface Evolver) for simulations.
• Studied self-assembly of single and multiple rods on a sessile liquid drop with cylindrical geometry.
• Varied particle properties: shape, contact angle, aspect ratio, and chemical heterogeneity.

Main Results:

• The curved interface effectively controlled rod orientation (parallel, perpendicular, oblique).
• Cylindrical geometry promoted tip-to-tip assembly for various rod shapes and patchy particles.
• Triblock patchy rods showed spatial confinement due to capillary repulsion.

Conclusions:

• Curved interfaces provide a facile strategy for manipulating rod-like particle configurations.
• This capillary assembly method enables the organization of particles into functional materials.
• The study demonstrates precise control over colloidal assembly through interfacial engineering.