Static and Dynamic Properties of Block-Copolymer Based Grafted Nanoparticles Across the Non-Ergodicity Transition

TL;DR

This study investigates the static and dynamic behaviors of block copolymer micelles with crosslinked cores, revealing how their properties evolve across the non-ergodicity transition using experiments and simulations.

Contribution

It introduces an effective brush interaction potential to accurately model the behavior of soft, core-shell nanoparticles, surpassing traditional star pair potentials.

Findings

The particles exhibit a transition from dilute to arrested states with distinct scattering and diffusion characteristics.

The effective brush potential aligns well with experimental and simulation data, capturing softness and dynamics.

The particles are positioned between ultrasoft stars and hard spheres in the softness spectrum.

Abstract

We present a systematic investigation of static and dynamic properties of block copolymer micelles with crosslinked cores, representing model polymer-grafted nanoparticles, over a wide concentration range from dilute regime to an arrested (crystalline) state, by means of light and neutron scattering, complemented by linear viscoelasticity. We have followed the evolution of their scattering intensity and diffusion dynamics throughout the non-ergodicity transition and the observed results have been contrasted against appropriately coarse-grained Langevin Dynamics simulations. These stable model soft particles of the core-shell type are situated between ultrasoft stars and hard spheres, and the well-known star pair interaction potential is not appropriate to describe them. Instead, we have found that an effective brush interaction potential provides very satisfactory agreement between experiments and simulations, offering insights into the interplay of softness and dynamics in spherical colloidal suspensions.