Steady state dynamic dependence between local mobility and non-affine fluctuations in two-dimensional aggregates

Area of Science:

• Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Collective behavior in self-propelled particles is complex, influenced by competing interactions.
• Camphor particle systems exhibit unique aggregate formation driven by capillary attraction and Marangoni repulsion.
• Understanding local dynamics within different aggregate morphologies is crucial for predicting collective behavior.

Purpose of the Study:

• To investigate the local dynamics of particles within generic 2D aggregate-forming systems.
• To characterize the temporal evolution of particle mobility and nearest-neighbor dynamics.
• To establish the relationship between particle mobility and local structural changes in compact and string-like aggregates.

Main Methods:

• Canonical ensemble, constant temperature molecular dynamics simulations were employed.
• The study focused on systems with competing short-range attraction and long-range repulsion.
• Key observables analyzed include particle mobility, Debye-Waller factor, and the non-affine parameter.

Main Results:

• Particle mobility and neighborhood dynamics were found to follow a power-law relationship (x⁻¹).
• The exponent of this relationship (1 or 2) correlates with the fractal dimension of compact and string-like aggregates.
• A functional dependence between mobility and local dynamics was statistically determined.

Conclusions:

• The study provides a quantitative link between individual particle motion and aggregate structure.
• Results are applicable to diverse self-assembling systems beyond camphor particles, including protein and nanoparticle systems.
• Insights contribute to understanding collective dynamics in glass-forming systems.