Professor of Chemical Engineering
Department of Chemical Engineering
muller2@berkeley.edu
510.642.4525

Research Expertise and Interest

chemical engineering, fluid mechanics, Rheology, complex fluids, microfabrication processes, Genetic Engineering of Protein Polymers, Finite Element Modeling of Bubbles, Stress Fluids, Taylor-Couette instabilities

Description

Our research interests focus on viscoelastic flows, rheology, and polymer dynamics. Broadly speaking, we are interested in how polymers behave in flows, especially in the complex flows typical of material processing operations. While simple molecular models may describe the behavior of a polymeric liquid in a rheometric experiment such as steady shear flow between parallel plates, calculations with these models generally fail to reproduce even the qualitative features of more complicated flows like extrusion and fiber- spinning. We use a variety of optical techniques including laser Doppler velocimetry, flow visualization, digital partical image velocimetry, and flow birefringence, along with rheometry, size exclusion chromatography, and light scattering. These tools allow us to study well-defined flows of well-characterized fluids and test quantitatively hydrodynamic calculations. By examining idealized problems, we hope to obtain an understanding of what elements in the constitutive models and calculations are essential for capturing the important physics in viscoelastic flows. Our aim is to obtain insights into the general mechanisms of instabilities and flow-induced demixing phenomena.

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