Crosslinking Driven Collapse Dynamics of Polyelectrolyte Single-Chain in Good Solvents

Electrostatics-mediated intramolecular crosslinking is proven effective for large-scale synthesis of single-chain nanoparticles (SCNPs) from polyelectrolyte chains in concentrated solutions. However, the underlying mechanism of crosslinking-driven collapse dynamics remains insufficiently explored. Here, we perform coarse-grained dissipative particle dynamics (DPD) simulations to unveil the crosslinking-driven collapse dynamics of a polyelectrolyte single-chain, which is dependent on chain length and electrostatic strength. It is shown that the timescale of the crosslinking-driven collapse follows a power-law dependence on chain length with a negative scaling exponent, which is fundamentally different from the solvent-induced collapse dynamics. We further explain this distinction by developing a Model A-type dynamics theory. A non-monotonic dependence of the collapse timescale on electrostatic strength is identified with the power-law scaling exponents being positive and negative in the weak and strong electrostatic coupling regimes, respectively. This is understood by the effect of counterion condensation within our dynamics model. The theoretical result helps to understand the electrostatics-mediated intramolecular crosslinking-driven collapse of single-chain and precisely control the microstructure of derived SCNPs.