Charge Regulated conformational properties of polyelectrolyte near an oppositely charged nanoparticle
Customizing the surface characteristics and stimuli-responsive behavior of nanoparticles with polyelectrolytes ushers in a new era across many aspects of our lives, ranging from advanced diagnostics to practical applications. Here, using hybrid CR Monte Carlo/ molecular dynamics simulations, we investigate how charge regulation can play a crucial role in shaping the adsorption dynamics of polyelectrolyte (PE) on oppositely charged nanoparticle (NP). We systematically investigate the influence of salt density, and polymer chain length on the PE-NP interaction. To complement CR results, we also perform molecular simulations under constant charge conditions. At high salt concentrations, CR enhances the adsorption of PE onto the NP surface, leading to a rapid decrease in the radius of gyration of PE; conversely, CC promotes the extended conformation of PE. No clear effect of PE length is observed at either low or high salt concentrations, whereas in CC simulations, the PE relaxes faster on the NP in the case of short chains. Furthermore, By comparing these results, we demonstrate that the MSD of PE follows a more direct path during adsorption implying a ballistic motion, whereas in the CC case, it exhibits subdiffusive behavior and delayed adsorption in both low and high salt density. Our findings indicates that 'tunable CR' is a robust strategy for controlling nanoparticle stability and interaction within a complex biochemical cues.