Today, with more than 1,600 members, SEPAWA^® Europe is one of Europe’s largest and most active professional associations supporting the interdisciplinary exchange of knowledge within the detergents/cleansers, cosmetics and fragrance industry.

SEPAWA Innovation prizes are awarded to encourage the active dissemination of new ideas within the SEPAWA community, while also enhancing public awareness of new technologies developed by member organizations.

In 2019 one of three SEPAWA Innovation Awards was presented to Prof. Dr. Andreas Klamt of BIOVIA Dassault Systèmes for his group’s innovative achievement with “COSMOplex: Self-consistent Simulation of Self-organizing Inhomogeneous Systems based on COSMO-RS” (Andreas Klamt, Johannes Schwöbel, Uwe Huniar, Larissa Koch, Selman Terzi and Théophile Gaudin).

Surfactants: Making Molecules “Slippery” in Industrial Applications

Surfactants are chemical compounds that decrease the surface or interfacial tension between two liquids, between a gas and a liquid, or between a liquid and a solid. They are used in detergents, wetting agents, emulsifiers, foaming agents and dispersants—and they are key factors in many critical industrial processes.

For example, scientists use surfactants to optimize the cleaning properties of detergents, while also reducing the amount of detergent required. They help paints to bond better on a variety of surfaces. In pharmaceutical formulations, they are used to stabilize drugs and alter reaction rates. Surfactants are used in agrochemical formulations such as herbicides, insecticides and hand sanitizers. They are even used as liquid drag reducing agents in pipelines.

Because of the great importance of surfactants, there are many theories and methods that attempt to predict the behavior of surfactant molecules and the formation of micelles, also known as aggregates of surfactant molecules dispersed in a liquid colloid. Most of these standard approaches rely on empirical concepts that can explain some trends in surfactant properties. However, a quantitative prediction of the behavior of a new surfactant can be challenging with an empirical approach, especially if the surfactant deviates significantly from the standard structures. Furthermore, empirical models often do not lend themselves to predicting the interaction of several components, and they are usually limited to water as a solvent.

COSMO-RS: A Thermodynamic Theory based on Quantum Chemistry

Prof. Dr. Klamt’s well-known COSMO-RS approach permits the a priori prediction of chemical potentials, activity coefficients and vapor pressures of almost any chemical compound in pure liquid solvents and mixtures. COSMO-RS obtains the information on intermolecular interactions from uni-molecular quantum chemical calculations of the particular solvent and solvate molecules; it is therefore largely independent of experimental data. Several major benchmark studies as well as the results of almost all blind prediction competitions have proven that COSMO-RS is currently the most predictive tool for distribution properties and solubilities in the liquid phase.

The SEPAWA Innovation Award recognized Prof. Dr. Klamt’s new COSMOplex method which extends COSMO-RS to inhomogeneous liquid systems such as interfaces, micellar systems and microemulsions. Because COSMOplex does not change anything in the fundamental description of the interactions, it should be as accurate as the underlying COSMO-RS method, which has already been proven in homogeneous systems.

COSMOplex: Ten Thousand Times Faster and Twice as Accurate

BIOVIA’s new COSMOplex method is four orders of magnitude faster and most likely two times more accurate than comparable molecular dynamics simulations. For these reasons, the method opens up a multitude of new possibilities for simulating and testing important properties of surfactants and detergent systems at the molecular level. The computing time for a COSMOplex simulation of a typical micelle formation and Critical Micelle Calculation (CMC) is in the order of a few hours on a standard laptop. Even microemulsions can be simulated on a laptop in one day. Mixed systems are no problem—making it possible for the first time to systematically investigate and screen the influence of chemical-structural changes in surfactants or additives or the effects of solvate enrichment.

COSMOplex has so far been validated mainly for neutral surfactants. Applications on ionic surfactants are technically feasible and show promising trends, but further development work is necessary at this point.

The COSMOplex method was published as an open-access article in “Physical Chemistry Chemical Physics” in April 2019, DOI:c9cp01169b, and previously filed as a patent.

COSMOplex is available today as efficient software from BIOVIA, Dassault Systèmes.