Engineering the Lotus Effect 2.0

What is the Lotus Effect 2.0?

Lotus leaf

The Lotus effect is well known from nature. It is used, among others, by the lotus flower (Nelumbo) and turns its leafs superrepellent for water. As a consequence, water cannot wet the surface of the leafs. However, this repellency only works for water. Liquids with significantly lower surface tensions (oils, organic solvents) will wet the surface of a lotus leaf. In order to hinder these liquids from wetting, fluorinated surfaces are required. The aim of this project is to engineer a new fluorinated material that allows superrepellency for a wide variety of liquids enabling this Lotus Effect 2.0

Fluoropor - a new generation of superrepellent fluoropolymers

Within this project, a new generation of fluoropolymers will be developed with the aim of creating coatings with superrepellent properties: Fluoropor.


The Young Investigator Group and the project “Fluoropor” are sponsored by the German Bundesministerium für Bildung und Forschung (Ministry of Education and Research) within the framework ”Vom Material zur Innovation (From Material to Innovation)”.

Is Fluoropor commercially available?

No - not yet. This project is a 4-year research project which has started in October 2014. Currently, there are various types of prototype materials under investigation, which differ in their physical, optical and chemical properties. In the following, some of the properties of these prototype materials will be highlighted.

Properties of Fluoropor

Transparent Fluoropor
Superhydrophobic transparent Fluoropor coating repels a stained water droplet
Oleophobic Fluoropor
A Fluoropor Surface repels organic solvents including DMF
A DMSO droplet jumping on a fluorpor coated surface
Fluoropor with switchable hydrophobicity
A superhydrophobic fluoropor surface (repelling a stained water droplet, top) becomes hydrophilib after switching (bottom). The process is reversible.
A Fluoropor coating on a glass slide
Transparent Fluoropor coatings on glass slides
Very low index of refraction
As most fluoropolymers, Fluorpor has a very low index of refraction which makes it appear “invisible” under water due to the index matching

Associated Publications

Journal Papers

Cover1F. Kotz, N. Schneider, A. Striegel, A. Wolfschläger, N. Keller, M. Worgull, W. Bauer, D. Schild, M. Milich, C. Greiner, D. Helmer, B. E. Rapp: “Glassomer: Processing Fused Silica Glass like a Polymer”, Advanced Materials, 30, 1707100, 2018 CoverLink

F. Kotz, P. Risch, D. Helmer, B. E. Rapp: “Highly Fluorinated Methacrylates for Optical 3D Printing of Microfluidic Devices”, Micromachines, 9, 3, 15, 2018 (invited) | Link

N. Keller, J. Bruchmann, T. Sollich, C. Richter, R. Thelen, F. Kotz, T. Schwartz, D. Helmer, B. E. Rapp: "Study of biofilm growth on slippery liquid infused porous surfaces (SLIPS) made from Fluoropor", ACS Applied Materials & Interfaces, 2018, accepted.

D. Helmer, N. Keller, F. Kotz, F. Stolz, C. Greiner, T. M. Nargang, K. Sachsenheimer, B. E. Rapp: „Transparent, abrasion-insensitive superhydrophobic coatings for real-world applications”, Nature Scientific Reports, 7, 1, 15078 | Link

C. Hannig, M. Dirschka, K. Länge, S. Neumaier, B. E. Rapp: "Synthesis and application of photo curable perfluoropolyethers as new material for microfluidics", Procedia Engineering, 5, 866-869, 2010 | Link


Books and Book chapters

Conference Contributions

P. Risch, F. Kotz, D. Helmer, B. E. Rapp: "3D printing of highly fluorinated methacrylates for the fabrication of transparent and chemically resistant microfluidic devices", poster, 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Kaohsiung, Taiwan, 2018.

D. Helmer, N. Keller, B. E. Rapp: “Photolithographic structuring of highly fluorinated polymers for the fabrication of microfluidic chips”, talk, 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Gyeongju, Korea, 2015

D. Helmer, N. Keller, B. E. Rapp: “Reversibly Photoswitchable Hydrophilic/Hydrophobic Surfaces”, talk, ECOSS, Barcelona, Spain, 2015

A. Waldbaur, M. Dirschka, K. Länge, B. E. Rapp: “Rapid prototyping of microfluidic structures from UV curable PTFE-like polymers – creating structures in direct lithography and casting”, poster, 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Seattle, USA, 2011

C. Hannig, D. Schild, M. Dirschka, K. Länge, B. E. Rapp: “PTFE-like/PDMS hybrids: synthesis of photocurable, highly chemically resistant polymers and their applications in microfluidics”, poster, 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Seattle, USA, 2011

C. Hannig, J. Bolle, K. Länge, M. Dirschka, B. E. Rapp: “PDMS and beyond – New ways to synthesis highly fluorinated polymers for use as resist or bulk material in microfluidics”, poster, Gordon Research Conference on Microfluidics, Physics & Chemistry, Boston, USA, 2011

B. E. Rapp, M. Worgull: “Combining indirect microfluidic systems with polymer components manufactured from photocurable perfluoropolyethers”, talk, Design, Test, Integration & Packaging (DTIP) of MEMS/MOEMS, Seville, Spain, 2010


B. E. Rapp, D. Helmer, C. Richter, N. Keller: "Hochfluorierte nanostrukturierte Polymerschäume zur Herstellung superabweisender Oberflächen", DE102016012001A1, 2016 | Link.

B. E. Rapp, D. Helmer, C. Richter, N. Keller: “Highly fluorinated nanostructured polymer foams for producing super-repellent surface”, WO2018065094A1, 2016 | Link.


D. Helmer, B. E. Rapp: "Superabweisende Oberflächen - Die Entwicklung eines superhydrophoben Werkstoffs", GIT Labor-Fachzeitschrift, 2018 | Link

D. Helmer, B. E. Rapp: "Healthcare Material Platforms", HEALTH 2, Paneuropean Network, 2017. The NeptunLab is features on the cover page of the issue | Link | Cover