Static and dynamic properties of block copolymer based grafted nanoparticles across the non-ergodicity transition

Abstract

We present a systematic investigation of static and dynamic properties of block copolymer micelles with cross-linked cores, representing model polymer-grafted nanoparticles, over a wide concentration range from a 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 those of 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.