Slippery Gels: Friction on Polymers

Friction is a very common force. It has been the subject of basic research since Leonardo Da Vinci; many aspects of its origin remain elusive, despite its everyday appearance and importance. Even Disney’s cartoonists understood this basic fact: in Uncle Scrooge’s story “Cash Flow”, the Beagle Boys try to steal Scrooge’s money by making it frictionless, and thus flow like water.


Figure 1: 3D drawing of a custom set-up to measure gel friction. These set-ups can be partially or completely 3D printed.

In this project we study the origin of friction on soft gel substrates. Such cross-linked macromolecular systems are typically slippery, and their frictional properties can even be tuned. A Bachelor thesis project in this context will expose you to rheology techniques and data analysis methods; furthermore you will have to synthesize different gels. Research Methods and Advanced Soft Matter are very helpful courses to provide background knowledge. If you are looking for a Master thesis project, you can also combine the aforementioned experimental work with numerical modeling with self-consistent field methods. Such efforts will be done under supervision of Frans Leermakers and require some background knowledge.

Friction on soft substrates is in fact a very rich subject and we have also developed many ways in which we can create custom rough substrates, whose frictional dynamics we still don’t understand.