COSMO-RS is quantum-chemically based method for the prediction of thermodynamic properties of pure and mixed homogeneous fluids. COSMO-RS calculates the thermodynamic data from molecular surface polarities, which result from DFT calculations of the individual components of the mixture. The different interactions of molecules in a liquid, i.e. electrostatic interactions, hydrogen bonding, and hydrophobic interactions are represented as functionals of surface polarities of the partners. Using a rigorous and efficient statistical thermodynamics method for such pair-wise surface interactions, COSMO-RS finally converts the molecular polarity information into standard thermodynamic data of fluids, i.e. vapor pressures, activity coefficients, excess properties, etc. COSMO-RS meanwhile is widely validated and accepted for the predictive exploration of fluid phase thermodynamics.

COSMOmic is an extension of COSMO-RS, which approximates self assembled structures as bio-membranes or micelles as layered liquids with different polarity composition in each layer. In this way, it enables the calculation of the distribution and of free energy profiles of solutes in biomembranes and other self-assembled structures in a much more efficient, and most likely at least as rigorous way as the standard force-field based simulation techniques. Application examples of this novel COSMOmic software for the partition coefficients and free energy barriers of solutes in bio-membranes and micelles will be shown. The influence of an elastic term and of the electrostatic Zeta-potential will be discussed.