Research

The overarching goal of all our activities is to model complex fluid behavior on different autonomous levels of description. By focusing on the essence of a problem, coarse graining provides understanding. Nonequilibrium thermodynamics is employed to establish the thermodynamic consistency of any proposed level of description ("second law" and beyond). Nonequilibrium statistical mechanics is tailored into a practical tool to relate material parameters on different levels by efficient and systematic computer simulations thus overcoming the problems associated with the existence of a wide range of time scales in complex fluids, in particular, polymeric liquids. We develop theoretical foundations in the context of relevant systems.

Rheology and Thermodynamics (GENERIC)

When aiming at the formulation of a complete system of balance and constitutive equations one is immediately faced with fundamental issues of nonequilibrium thermodynamics. »»

Guided Simulation Methods

What is the goal of computer simulations of beyond-equilibrium systems, how should they be performed, and how can they be employed most efficiently? A key concept to their solution seems that of beyond-equilibrium ensembles. »»

Statistical Physics of Complex Fluids

Nonequilibrium molecular dynamics and Brownian dynamics computer simulations are involved to solve the equations of motion for diluted or concentrated polymeric systems modeled by simple microscopic models such as ensembles of multibead chains. »»

Nonequilibrium thermodynamics of glasses

When investigating glasses, nonequilibrium phenomena are ubiquitous. We hence apply the modern framework of nonequilibrium thermodynamics to find out whether we might be able to raise our level of understanding of glasses, both from the conceptual and from the practical points of view. »»

Large Deformation Behavior of Semi-crystalline Polymers

Due to the complexity of the intertwined structural changes during large deformation of semi-crystalline polymers, a multiscale approach seems indispensable in order to obtain an adequate model. Particularly, we propose to combine thermodynamics, coarse-graining techniques, and computer simulations, which will lead to a more profound understanding of the dynamics. »»

Experimental Fluid Dynamics

Fluid dynamics of polymer melts connects the melt rheological behaviour with polymer processing. Whereas in the literature there has been research in the theoretical field, we will focus on improving the experimental techniques. »»

New Models in Polymer Kinetic Theory

When the models of polymer kinetic theory are formulated in terms of stochastic differential equations one cannot only investigate established models but one can also develop new models. »»

Minimal Hydrodynamics

A kinetic description such as Boltzmann equation, in terms of one particle distribution function, is a useful bridge between a completely molecular description or a complete macroscopic description. However, a direct discretization of kinetic equations for solving hydrodynamic problems of engineering interests is still a monumental task »»