Evonik lecture series @ MaWi-Kolloquium

Dr. Joachim Venzmer
Fellow Interfacial Technology
Evonik Operations GmbH

Examples of Industrial Colloid & Interface Science:

• Biosurfactants – Greenwashing or Green Washing?
• Superspreading of Trisiloxane Surfactants – Solving a 35 Year Old Mystery!

Biosurfactants such as Rhamnolipids are not only based on sustainable feedstocks, but are also produced by microorganisms. The basic phys-chem surfactant properties such as surface activity or micelle formation, however, are not sufficient to predict the suitability of biosurfactants for specific applications. Substituting a small portion of the classical surfactants by biosurfactants in application fields such as laundry detergents and cosmetics is more or less only greenwashing. It will be explained why the full potential of biosurfactants can only be unleashed by using completely new formulation concepts – and then, there is the opportunity for really green washing.

Superspreading of some trisiloxane surfactant solutions on hydrophobic substrates has attracted much attention both from a theoretical point of view and the practical applications e.g. for agrochemical formulations. Despite considerable efforts of many groups worldwide, the mode of action has remained a mystery for the last 35 years. Very recently, in collaboration with Emanuel Schneck/TU DA, the crucial difference between superspreading and non-superspreading surfactants could be revealed by using Neutron reflectometry at ILL. These fascinating results have even been selected to be “Editor’s Choice” of Langmuir in November 2025 (https://doi.org/10.1021/acs.langmuir.5c03781)!

Get-together after the lecture with refreshments.