(30a) Transport and Phase Transformation in Surfactant Systems

Various intriguing phenomena involve simultaneous transport and phase transformation. As one phase grows at the expense of another, transport may produce interfacial instability. When two phases with different compositions are brought into contact in multicomponent systems, diffusion may produce regions of local supersaturation, resulting in spontaneous emulsification or isolated precipitation. In some systems such as many involving surfactants, complexity of the phase diagram leads to formation of ?intermediate? phases not present initially near the initial surface of contact and sometimes their subsequent dissolution. Many phases involved in these phenomena have microstructure, which influences both the rates of growth and dissolution processes and the morphologies produced. Such phenomena and their role in applications will be discussed, including their growing importance, for instance in nanoemulsion formation, as behavior at smaller scales becomes ever more relevant in producing desired products.