Kinetic arrest in polyion-induced inhomogeneously charged colloidal particle aggregation

Area of Science:

• Colloid and Polymer Science
• Physical Chemistry
• Computational Materials Science

Background:

• Polymer chains adsorbed on charged colloidal particles alter inter-particle forces, potentially reversing electrostatic repulsion into attraction.
• Sufficient polymer adsorption can lead to the formation of large colloidal aggregates.
• This attraction arises from correlated polyion adsorption, creating non-homogeneous surface charge distributions.

Purpose of the Study:

• To investigate the aggregation kinetics of polyion-induced colloidal complexes.
• To understand the role of charge anisotropy in colloidal aggregation.
• To interpret experimentally observed cluster phases in polyelectrolyte-liposome solutions.

Main Methods:

• Monte Carlo simulations were employed to model the aggregation process.
• A DLVO-like inter-particle potential, accounting for charge anisotropy, was utilized.
• The potential was based on the model proposed by Velegol and Thwar (Langmuir 17, 7687 (2001)).

Main Results:

• The aggregation kinetics were found to slow down as the process progressed.
• This deceleration is attributed to an increasing potential barrier height with cluster formation.
• The simulation results provide a framework for understanding kinetic arrest in colloidal systems.

Conclusions:

• The study elucidates the mechanism of polyion-induced colloidal aggregation.
• Charge anisotropy significantly influences aggregation kinetics by increasing potential barriers.
• Observed cluster phases in polyelectrolyte-liposome solutions can be explained as kinetically arrested states.