PHASE-SEPARATION AND COALESCENCE IN CRITICALLY QUENCHED ISOBUTYRIC-ACID-WATER AND 2,6-LUTIDINE-WATER MIXTURES

Light scattering was used to study phase separation in critically quenched mixtures of isobutyric-acid water and 2,6-lutidine water. The measurements spanned the time interval 10 103 s and quench depths from 0.7 to 9 mK. The parameters measured were km(t), i.e., the photon momentum transfer at the angle of maximum scattering, and the ring intensity I(km,t). The early-stage measurements of km vs t are in very good agreement with the calculations of Kawasaki and Ohta and with the coalescence model of domain growth, which gives km-, with =13. In the late stage increases to unity in both systems. This implies that hydrodynamic effects control the rate of growth of the nucleating domains of size l km-1. In both early and late stages, the intensity measurements are consistent with I(km,t). The scattering experiments were supplemented by direct observation of domain growth with a microscope. © 1979 The American Physical Society.