Role of brush architecture on the dffusiom kinetics of brush particles in the melt state

The organization of polymer-grafted particles (aka 'brush particles') provides a framework for the controlled assembly of multi-component particle systems into a range of microstructures hybrid materials with novel photonic or phononic properties. Fundamental to the controlled fabrication of these novel hybrid materials is understanding of the role of the kinetic properties of of brush particles in the melt state on the structure formation process.

This contribution will present the first direct measurement of the diffusion coefficient of brush particles in the pristine melt state by the analysis of layer spread kinetics of brush particle bilayer structures. Partial deuteration in conjunction with a novel organosilica chemistry was used to facilitate a library of brush particles with identical chemical composition and a matched, but systematically varied, scattering length density of core and brush-shell. Neutron reflectivity was used to determine the spreading kinetics of brush particle bilayer structures. Evaluation of the diffusion coefficient of brush particles with systematically varied architectures reveals a distinctive slow-down as compared to star-polymer analogs. The slower kinetics is attributable to the presence of the impenetrable core and shown to rationalize the evolution of microstructure in phase-separated multicomponent brush particle films.