Frustrated coalescence in a chemically reactive polymer blend film

The phase separation of a thin polymer blend layer undergoing a simultaneou s transesterification reaction is examined by a variety of experimental tec hniques [neutron and X-ray reflectivity, optical microscopy, atomic force m icroscopy (AFM)] to determine morphological features unique to reactive pha se separation. Neutron reflectivity measurements suggest; that a copolymer layer reactively forms at the interface between the phase-separating blend components. Evidence for a copolymer layer is also provided by AFM and opti cal images which indicate a strong inhibition ("frustration") of droplet co alescence and a tendency of the droplets to cluster in late-stage phase sep aration. The influence of the transesterification reaction on phase separat ion is found to depend strongly on temperature.