Nanotechnology

Nanotechnology and its application in products and processes has become a buzzword for industrial development. Nanotechnology refers to systems that are smaller than 100 nanometers in at least one spatial dimension. Such systems are characterized by the large ratios between surface area and volume, which results in an overwhelming number of properties that are not present in materials having greater volumes. The corresponding result is the nearly infinite potential for product and process improvements, which have not even been remotely investigated scientifically.

Our department has begun to couple our competence in mathematical optimization with nanotechnology to make these special properties that result from large ratios between surface area and volume, available for industrial purposes. In previous projects, we have followed a general approach: Simulations directly on a nanoscale, usually with methods that move every single relevant atom, allow the study of the fundamental properties of a nano-system and further processing in a substitute model, which then works on a macroscopic process scale.

In this process, the nano effects are hidden, for example, in effective material parameters. Aided by the substitute models, the processes and products can be optimized on a multi-criteria basis thereby avoiding, at least partially, costly experimentation while at the same time proposing virtual optimal process and product designs.

Example Projects

Molecular Modelling and Simulation in Process Engineering

Molecular methods in the modeling of fluids based on empirical force fields allow for the simulation of intricate engineering problems. The quality and predictive power of these methods crucially depend on the quality of the force field. The necessary force field parameter fits, usually by using experimental liquid-vapor equilibrium data, are up to now not done on a rigorous mathematical basis.

The use of molecular modelling and simulation in process engineering is depending on the availability of suitable molecular models for the characterization of the materials. We develop such models by using our experience on multi criteria optimization, data on the materials and molecular simulation. For example, some applications of the models are the characterization of

  • Surfaces
  • Boundary Surface
  • Electrolyte Solution
  • Hydrogen Bond Builiding Systems
  • Hydrogels.

The closed EU project NANOPUR develops an active ultra filtration membrane for the efficient filtration of drinking water. 12 partners from seven countries collaborate in the development of nano-structured membranes that combine high permeability and high filter selectivity.

ITWM has started to model the membrane characteristics on a nano-scale. Molecular modeling can identify structure-property relationships for Zeta potentials and flow potentials; both attributes are experimentally difficult to access, but are needed to define the filtration properties of the membranes. By taking advantage of appropriate molecular correlations, wall rheology models are developed that can be used as boundary conditions in the mesoscale models of fluids transport and particle deposit simulations.

On the basis of these meso models, the Flow and Material Simulation Department at ITWM calculates on the macro level, the component level, the Key Performance Indicators (KPI) for the water filtration. From a technological perspective, these are the energy consumption, fouling, and filter efficiency (selectivity). To support the commercialization of the developed membranes, the KPIs are extended by empirical cost and risk assessments. Since all quality and cost dimensions cannot be simultaneously optimized, the concept of Pareto optimality (best possible compromise) is used and a comprehensive decision support tool will be developed.