KINETICS OF NUCLEATION AND GROWTH IN A NEAR-CRITICAL BINARY-LIQUID MIXTURE AT REST AND UNDER A SHEAR-FLOW

Nucleation and growth in a mixture of isobutyric acid and water are studied by small-angle light scattering under a shear flow. The study is restricted to off-critical quenches, just below the coexistence curve,where nucleation is essentially heterogeneous. When no shear is applied, the distribution of the droplet radii is peaked around its mean value, which behaves as R (t) = R0t(a), with a = 0.6+/-0.1. A continuous shear flow is shown to accelerate the growth. An advection-diffusion process is proposed, which allows the data to be expressed in a scaled form, over a wide range of shear-rates. The effects of shear-induced coalescence and gravity-induced flows are also investigated.