COSMOplex is a unique methodology extending COSMO-RS far into the regime of inhomogeneous systems. By combining the chemical potential from COSMO-RS with molecules volumes and pressures in a given simulation geometry, the molecules distribute in space until equilibrium is reached. By this approach COSMOplex yields results usually generated by molecular dynamics, but at virtually no cost. COSMOplex is up to 10,000 times faster than molecular dynamics in many cases and covers a full range of inhomogenous systems, providing access to a series of physical-chemical properties.

Key features of COSMOplex

  • Complete self-consistent assembly of molecules without external input
  • Prediction of micelle formation including critical micelle concentrations
  • Membrane formation including free energy distribution of solutes
  • Microemulsion systems
  • Together with COSMOperm membrane permeation and the effect of penetration enhancers can be predicted
  • Liquid-liquid interfaces


Surfactant containing system such as (micro)emulsions, micelles and membranes can be handled with COSMOplex. The first example to the right shows the distribution of oil, surfactant and water in a microemulsion system as simulated with COSMOplex and second example the correlation of the predicted critical micelle correlation (CMC) with experimental data.


In the same way as COSMOplex can simulate the self-assembly of surfactants to a micelle, it can predict a biomembrane consisting of different membrane components, e.g. phospholipids, ceramides etc. It can even include small molecules such as penetration enhancers or potentially toxic molecules. The example shows the predicted permeation of UV-filter molecules through skin, where COSMOplex was used to generate the bio-membranes and COSMOperm and COSMOtherm were used for diffusion constants, free energies and partitioning coefficients, which are all required for the used skin permeation model.


Due to its ability to simulate inhomogeneous systems, COSMOplex can also predict the concentration profile at a liquid-liquid interface and even the average orientation of the molecules. The left graph illustrates the internal pressure profile at the interface, which directly corresponds to the interfacial energy. By applying an additional correlation function, the interfacial tension between two liquid mixture can thus be predicted in a straight forward manner. The liquids can be complex and even contain surfactants.