Activity-controlled annealing of colloidal monolayers.

Area of Science:

• Materials Science
• Soft Matter Physics
• Active Matter

Background:

• Molecular motors are crucial in biological systems, driving transport and assembly through internal fluctuations.
• Active colloids, engineered to move using consumed energy, offer potential for self-powered man-made materials.
• The application of active colloids in materials science remains underexplored.

Purpose of the Study:

• To investigate the impact of self-propelled microparticles on the annealing process of passive materials.
• To explore the potential of internal activity for controlling material properties and dynamics.

Main Methods:

• Experimental observation of a passive bead monolayer annealed with added self-propelled microparticles.
• Theoretical modeling of particle collisions to explain the observed acceleration of annealing.
• Brownian dynamics simulations to compare with experimental results and reveal underlying mechanisms.

Main Results:

• A massive acceleration in the annealing of a passive bead monolayer was observed with the addition of self-propelled microparticles.
• A collision-based model successfully rationalized the active fluctuations driving and activating the annealing process.
• Brownian dynamics simulations revealed a dynamical transition in annealing mechanisms and active dopant localization (uniform distribution or grain boundary co-localization).

Conclusions:

• Internal activity from self-propelled particles can be harnessed to significantly control and accelerate material processes like annealing.
• The findings demonstrate the potential of active matter in materials science, moving beyond equilibrium principles.
• This work lays the foundation for developing novel materials with built-in, controllable activity.