Effects-of-reversible-chemical-reaction-on-morphology-and-domain-growth-of-phase-separating-binary-mixtures-with-viscosity-difference.pdf

Effects of Reversible Chemical Reaction on Morphology and Domain Growth of Phase Separating Binary Mixtures with Viscosity Difference Yanli Huo,*a Hongdong Zhang, Yuliang Yang Department of Macromolecular Science, Key Lab of Molecular Engineering of Polymers, SMEC, Fudan University, Shanghai 200433, China Fax: þ 86 (21) 6565-5123; E-mail: ylhuo@fudan.edu.cn Received: September 24, 2003; Accepted: December 12, 2003; DOI: 10.1002/mats.200300021 Keywords: morphology; phase separation; reversible chemical reaction; viscosity difference I. Introduction Phase separation of ordinary binary mixtures, including binary small molecules and polymer blends, has been intensively studied from both experimental and theoretical viewpoints over the past decades,[1] since the resulting morphologies of phase separation play a key role in determining the properties of the mixtures. Usually, the two components of a binary mixture do not possess exactly equivalent characteristics, and there are some differences between them. The existing differences include the viscoelasticity contrast between the two phases of polymer solutions[2] and polymer blends with different glass transition temperature,[3] elasticity difference of a binary alloy,[4] and viscosity difference of a binary fluidmixture.[5] Studies about above systems showed that the difference between two components could lead to some drastic changes of domain morphology. To get more interesting Summary: The effects of a reversible chemical reaction on morphology and dynamics of phase separating binary mix- tures with viscosity difference are studied by numerically solving modified time-dependent Ginzburg-Landau and Navier-Stokes equations. Much more interesting morpholo- gies are observed in the system due to the coupling of rever- sible chemical reaction and viscosity difference between two components. When the chemical reaction rate is relatively low, the impact of viscosity difference on morphologies is prominent, so that the resulting patterns are affected by both reversible c