Thermodynamics and kinetics of competing aggregation processes in a simple model system

Area of Science:

• Physical Chemistry
• Chemical Kinetics
• Surface Science

Background:

• Aggregation processes, both in bulk solution and on surfaces, are fundamental in various scientific fields.
• Understanding the interplay between these processes is critical for applications ranging from materials science to biological systems.
• Previous models often treated these aggregation pathways separately, limiting insights into their competitive dynamics.

Purpose of the Study:

• To develop a theoretical model for comparing the thermodynamics and kinetics of bulk and surface aggregation.
• To identify the conditions under which solution-phase aggregation dominates over surface aggregation, and vice versa.
• To provide insights into competitive aggregation phenomena relevant to biological interfaces, such as cell membranes.

Main Methods:

• Development of a simple theoretical model for stepwise monomer aggregation.
• Analysis of adsorption and desorption kinetics at the solid-fluid interface.
• Focus on the high friction limit, relevant for processes in liquid environments.
• Comparison of the thermodynamic and kinetic parameters governing bulk versus surface aggregation.

Main Results:

• The model successfully captures competing aggregation pathways in both fluid bulk and on a solid surface.
• Key thermodynamic and kinetic parameters were derived for each aggregation process.
• Conditions favoring either bulk or surface aggregation were identified based on these parameters.
• The high friction limit provides a framework for understanding aggregation in realistic liquid media.

Conclusions:

• A unified theoretical framework can describe competing bulk and surface aggregation processes.
• The relative rates and stability of aggregates dictate whether solution or surface aggregation prevails.
• This work offers valuable insights for understanding aggregation phenomena at interfaces, including biological membranes.