Quantitative Analysis of Interdigitation Kinetics between a Polymer Melt and a Polymer Brush

We present an investigation of the swelling dynamics of end-grafted hydrogenated polystyrene (h-PS) chains confined between a solid substrate and a deuterated polystyrene (d-PS) melt, based on neutron reflectometry experiments. The segment density profile of the grafted chains was measured for different annealing times. The kinetics of relaxation was quantified by measuring the amount of melt chains that have crossed the initial h-PS/d-PS sharp interface as a function of the annealing time. The dependence of this kinetics versus the molecular weight of the grafted chains, the melt chains, and the grafting density is investigated and compared to a proposed scaling model inspired from the previous work of Milner, McLeish, and O'Connor.(1,2) Moreover, the relaxation kinetics is found to highly depend on the polydispersity of the polymer brushes, and we propose a way for taking that parameter into account.