Influence of Rotational Diffusion on Macromolecular Self-Assembly Kinetics

Abstract

Macromolecular self-assembly underlies a plethora of biological processes and provides a versatile route for fabricating functional soft materials. The kinetics of self-assembly in solution are inherently stochastic and are fundamentally governed by the interplay of translational and rotational diffusion of the constituent macromolecules. While most computational studies model macromolecules as patchy spherical colloids, thereby neglecting the influence of polymer architecture and internal conformational dynamics, the role of these factors in macromolecular self-assembly kinetics remains poorly understood. Here, we investigate the self-assembly of two patchy macromolecules with different architectures, namely linear chains and star polymers with four and seven arms. The hydrodynamic radii of the macromolecules are chosen to be nearly identical, thereby matching their translational diffusion coefficients and thus isolating the influence of rotational diffusion on the self-assembly process. The binding probability of the patchy macromolecules is found to depend strongly on their internal architecture. Furthermore, reactive path density analysis reveals that self-assembly pathways are influenced by the rotational diffusion coefficient of the individual macromolecules. Overall, this study establishes a bridge between the equilibrium dynamics of macromolecules and their self-assembly kinetics, highlighting the importance of polymer internal architecture in the process of self-assembly.