Universality of scaled structure functions in quenched systems undergoing phase separation

We present a novel heuristic “universal” formula for the scaled structure function following a quench into the miscibility gap which gives very good fits to a variety of experimental observations. The single adjustable parameter γ needed to fit data for alloys, binary fluids, polymer mixtures and computer simulation curves depends essentially only on the fraction of the volume of the minority phase. Minimizing the ratio of “surface area to volume” of the minority phase predicts a rough morphology of the system—its local character changes from spherical isolated droplets to interconnected plate-like objects as the minority fraction increases. By relating γ to this microstructure we obtain the value of γ correctly to within 10%.