Controlling the shape and topology of two-component colloidal membranes

Area of Science:

• Soft matter physics
• Materials science
• Biophysics

Background:

• Self-assembled membranes are crucial in biology and engineering.
• Colloidal membranes mimic lipid bilayers with fluid dynamics and bending elasticity.
• Their scale allows studying membrane assembly and reconfiguration.

Purpose of the Study:

• Investigate how doping colloidal membranes with rods affects their geometry and topology.
• Understand the mechanisms driving shape and topological transformations.
• Explore potential applications in controlling elastic sheet properties.

Main Methods:

• Doping colloidal membranes with short, miscible rods.
• Observing shape changes using microscopy.
• Applying theoretical modeling to understand energetics.
• Analyzing topological transformations during coalescence.

Main Results:

• Doping transforms disk-shaped membranes into saddle-shaped surfaces (Enneper's minimal surfaces).
• Formation is driven by increased Gaussian modulus, controlled by rod fraction.
• Coalescence leads to diverse topological structures (catenoids, trinoids, etc.).
• A system-spanning, sponge-like phase forms at long timescales.

Conclusions:

• Colloidal membranes offer a platform to study real-time topological transformations.
• Compositional heterogeneity induces emergent elasticity, enabling shape and topology control.
• Results demonstrate a pathway for engineering thin elastic sheets with tunable properties.