Real Space Measurement of Structure in Phase Separating Binary Fluid Mixtures

In off-critical binary fluid mixtures undergoing phase separation, a polydisperse set of minority phase domains grows in a matrix of the majority phase. With confocal microscopy and digital image processing, we have made direct three-dimensional measurements of structure in phase separated mixtures of low molecular weight polymers. The distribution of domain sizes and the spatial correlations in these mixtures exhibit dynamic scaling, implying that the coarsening may be viewed entirely as an increase in length scale. This coarsening process appears to be driven by aggregation of domains.