Dynamic capillary assembly of colloids at interfaces with 10,000g accelerations

Area of Science:

• Soft Matter Physics
• Colloidal Science
• Non-equilibrium Dynamics

Background:

• High-rate deformation is crucial for understanding shock, fracture, and phase transitions in soft matter.
• Two-dimensional colloidal monolayers offer a model system for studying soft matter behavior, but typically under slow deformation.
• Previous research has lacked insight into colloidal dynamics under extreme, high-rate conditions.

Purpose of the Study:

• To investigate the evolution of a colloidal monolayer under high-rate deformation.
• To visualize and understand the emergent behaviors of colloids driven by ultrasound.
• To explore the underlying physical mechanisms, including dynamic capillarity and hydrodynamic interactions.

Main Methods:

• Utilized a monolayer of colloidal particles confined at a bubble surface.
• Applied high-rate deformation using ultrasound.
• Employed discrete particle simulations to model particle interactions and dynamics.

Main Results:

• Observed the emergence of a transient network of strings during high-rate deformation.
• Demonstrated that dynamic capillarity and hydrodynamic interactions drive string formation.
• Provided evidence of inertial effects in the colloidal system, with accelerations up to 10,000g.

Conclusions:

• High-frequency ultrasound induces complex dynamics and transient network formation in colloidal monolayers.
• Inertial effects play a significant role in colloidal systems under extreme deformation.
• Extreme soft matter deformation presents novel avenues for dynamic self-assembly and pattern formation.