Condensed Matter Theory

Abstract:

Simulations show that, when a phase-separated binary [Formula presented] fluid is driven to flow past chemically patterned substrates in a microchannel, the fluid exhibits unique morphological instabilities. For the pattern studied, these instabilities give rise to the simultaneous, periodic formation of monodisperse droplets of [Formula presented] in [Formula presented] and [Formula presented] in [Formula presented]. The system bifurcates between time-independent behavior and different types of regular, nondecaying oscillations in the structural characteristics. The surprisingly complex behavior is observed even in the absence of hydrodynamic interactions and arises from the interplay between the fluid flow and patterned substrate, which introduces nonlinearity into the dynamical system. © 2003 The American Physical Society.