Bioinspired self-assembled colloidal collectives drifting in three dimensions underwater

Area of Science:

• Soft Matter Physics
• Materials Science
• Robotics

Background:

• Active matter systems exhibit emergent collective behaviors like self-assembly and migration.
• Achieving stable, three-dimensional (3D) locomotion of synthetic active matter without external support is challenging due to dispersion.

Purpose of the Study:

• To develop a bimodal actuation strategy for controllable 3D collective movement in artificial colloidal systems.
• To overcome dispersion challenges in free-space locomotion of synthetic active matter.

Main Methods:

• Utilized magnetic fields to induce self-assembly of magnetic colloidal particles into stable, dynamic entities.
• Employed optical fields to generate photothermal effects, creating convective flow for particle collective propulsion.
• Investigated locomotion capabilities in various aquatic environments (underwater, water-air interface, water surface).

Main Results:

• Successfully formed dynamically stable colloidal collectives capable of 3D locomotion.
• Demonstrated controlled movement underwater, at the water-air interface, and on the water surface.
• Validated the bimodal actuation strategy for collective migration in fluidic environments.

Conclusions:

• The proposed magnetic and optical field strategy enables robust, controllable 3D collective movement of synthetic active matter.
• This research offers a novel approach for designing smart materials and devices with coordinated locomotion capabilities.
• Provides insights into engineering synthetic active matter for complex 3D environments.