Molecular dynamics investigation of the condensation kinetics of molecular fluids

• Applicant: Professor Dr. Ulrich K. Deiters, since 10/2008
• Subject Area: Chemical and Thermal Process Engineering
• Term: from 2003 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5406639

• Final Report Year: 2012

Final Report Abstract

Three main results are obtained in the areas homogeneous methanol nucleation, heterogeneous nucleation, and Ostwald ripening. Using molecular dynamics simulation the nucleation process, i.e. the formation of the first clusters of the new phase, has been analysed for the polar substance methanol. Here the influence of the cluster structure due to the weak amphiphilic character of methanol on the nucleation has been analysed. The heterogeneous nucleation of argon on polyethylene has been analysed as a model system. The transition from two-dimensional to three-dimensional nucleation is observed. Special focus of this work was on the heat transfer between the nucleating substance and the substrate which has been analysed by direct MD simulation. In the third part the onset of Ostwald ripening has been observed when the smaller cluster has reached a lower critical size. In addition, the enhancement of ripening by induced fluctuations has been analysed.

Publications

• Molecular dynamics simulation of heterogeneous nucleation and growth of argon at polyethylene films, Journal of Physical Chemistry C, Vol. 111. 2007, Issue 43, pp 15784–15791.
  R. Rozas, T. Kraska
  
• Direct observation of single Ostwald ripening processes by molecular dynamics simulation, Journal of Physical Chemistry B, Vol. 112. 2008, Issue 39, pp 12408–12413.
  T. Kraska
  
• Investigation of The Nucleation and Growth of Methanol Clusters from Supersaturated Vapor by Molecular Dynamics Simulations. Soft Materials, Vol. 10, Issue 1-3, pp. 130-152.
  F. Römer, B. Fischer, T. Kraska