Crowded Solutions of Single-Chain Nanoparticles under Shear Flow

TL;DR

This study uses computer simulations to explore how shear flow affects the structure and dynamics of single-chain nanoparticles in semidilute solutions, revealing unique scaling laws and behaviors distinct from linear polymers.

Contribution

First simulation-based investigation of shear flow effects on SCNPs, uncovering distinct concentration-dependent scaling laws and non-monotonic crowding responses.

Findings

SCNPs exhibit different shear rate dependence than linear chains.

Two distinct scaling regimes are identified below and above overlap concentration.

SCNPs show non-monotonic swelling behavior under shear at high Weissenberg numbers.

Abstract

Single-chain nanoparticles (SCNPs) are ultrasoft objects obtained through purely intramolecular cross-linking of single polymer chains. By means of computer simulations with implemented hydrodynamic interactions, we investigate for the first time the effect of the shear flow on the structural and dynamic properties of SCNPs in semidilute solutions. We characterize the dependence of several conformational and dynamic observables on the shear rate and the concentration, obtaining a set of power-law scaling laws. The concentration has a very different effect on the shear rate dependence of the former observables in SCNPs than in simple linear chains. Whereas for the latter the scaling behavior is marginally dependent on the concentration, two clearly different scaling regimes are found for the SCNPs below and above the overlap concentration. At fixed shear rate SCNPs and linear chains also respond very differently to crowding. Whereas, at moderate and high Weissenberg numbers the linear chains swell, the SCNPs exhibit a complex non-monotonic behavior. These findings are inherently related to the topological interactions preventing concatenation of the SCNP loops, leading to less interpenetration than for linear chains.