1. Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX4 4QD, Exeter, UK
2. Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, D-79110 Freiburg, Germany
3. Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen, Norway
4. Cluster of Excellence livMatS @ FIT, Freiburg, Germany
5. Fraunhofer IWM, MikroTribologie Centrum μTC, Freiburg, Germany