Monday, November 5, 2007 - 1:21 PM

Cosmomic: Simulation Of Bio-Membranes And Micelles With Cosmo-Rs

Andreas Klamt1, Michael Diedenhofen2, and Uwe Huniar2. (1) COSMOlogic GmbH&CoKG, Burscheider Str., Leverkusen, 51381, Germany, (2) COSMOlogic GmbH & Co. KG, Burscheider Str. 515, Leverkusen, Germany

COSMO-RS is a novel predictive method for the thermodynamic properties of pure and mixed fluids. COSMO-RS calculates the thermodynamic data from molecular surface polarities, which result from quantum chemical calculations of the individual compounds in the mixture. The different interactions of molecules in a liquid, i.e. electrostatic interactions, hydrogen bonding and dispersion, are represented as functions of surface polarities of the partners. Using a novel, very rigorous and efficient thermodynamic solution for such pair-wise surface interactions, which goes beyond the limitations of the quasi-chemical approximation, COSMO-RS finally converts the molecular polarity information into standard thermodynamic data of fluids, i.e. vapor pressures, activity coefficients, excess properties, etc. Winning the COSMOlogic First Industrial Fluid Properties Simulation Challenge organized by NIST and AICHE/COMSEF, COSMO-RS has proven to be the most reliable and efficient tool for the prediction of activity coefficients and similar thermodynamic properties of demanding compounds.

Originally COSMO-RS was developed for homogeneous bulk fluids. Nevertheless, by considering self assembled structures as bio-membranes or micelles as layered liquids with different polarity composition in each layer, COSMO-RS can be extended to the calculation of the distribution of solutes in such self-assembled structures. First application examples of this novel COSMOmic software for for the partition coefficients and free energy barriers of solutes in bio-membranes and micelles will be shown.

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