Compatibility of a statistical copolymer p(EMA-CO-MMA) with PS and PMMA

The compositions of coexisting phases and the interface widths in blends of a statistical copolymer of poly(ethylmethacrylate — co — methylmethacrylate) (P(EMA_1,x-co-MMA_x)) and a deuterated polystyrene (PS(D)) as well as a deuterated poly(methylmethacrylate) (PMMA(D)) have been investigated by neutron reflectometry (NR). Interaction parameters are calculated from the compositions of coexisting phases and the interface width values. Utilizing a novel two dimensional scheme for graphical representation of the interaction parameters, the results are in very good agreement with studies on the interaction parameters for PS/PMMA, PS/PEMA and PEMA/PMMA blends. In particular, X_EMA/MMA deduced from a NR experiment on a P(EMA-block-MMA(D)) diblock copolymer fits excellent into the scheme.