Biomimetic Surfaces and Scanning Probe Technologies

apl. Prof. Dr. Hendrik Hölscher [Contact]

Welcome

… to our interdisciplinary group studying phenomena found on natural and artificial surfaces. We are experts in characterization of mechanical, physical, and chemical properties of surfaces on nano- and microscales. We discover the secrets of plants and animals ranging from water ferns to butterflies, beetles, and snakes. Based on this knowledge, we develop biomimetic surfaces for technical applications. Furthermore, we are passionate about developing and building fancy scanning probe microscopes.

Two examples comparing the natural archetype with the respective artificial surface, mimicking the nano- and microstructure of a blue *Morpho* butterfly (left) and a white beetle (right)

Biomimetic Surfaces

Through evolution, many plants and animals developed surfaces with astonishing properties caused by nano- and microstructures. Prominent examples include the brilliant structural colours found on several butterfly wings and the sticky toes of geckos. Some of these natural archetypes are multifunctional, i.e., they serve different purposes at the same time. The idea of biomimetics is to discover prototypes for the development of smart technical surfaces. Our special interest is to design biomimetic surfaces as facilitators for a cleaner environment.

Dry Self-Cleaning of Photo-voltaic Modules

Many snakes feature nano-scale fibril structures on their scales. They are only some 10 nm high and feature a periodicity of some µm. Although they cannot be observed in the visible range and the surfaces appear smooth to the naked eye, these nano-steps cause significant anisotropic frictional properties that are helpful for the locomotion of snakes. These nano-step structures can be copied to artificial polymeric surfaces, which can be utilized for the dry self-cleaning of photo-voltaic modules.

Replacement of TiO2 by Bio-inspired Foamed Polymers

White beetles of the genus Cyphochilus are well-known for their scales, producing a nearly perfect whiteness in a very efficient way with an astonishing low amount of material. Inspired by this biological architecture, we developed two techniques allowing for the fabrication of ultra-thin, yet highly scattering, white polymer films and particles. Both approaches can be utilized for various applications, ranging from extremely white but ultra-thin coatings to scattering particles as possible replacements for titanium dioxide.

Multifunctional Nanofur

Many plants and insects possess multifunctional surfaces covered with dense fur of nanoscale hairy structures. Such nanofur is of high interest for various biomimetic applications like self-cleaning, self-healing, air retention, and oil-water separation. We developed a highly scalable and competitive role-to-role technique for the fabrication of biomimetic nanofur. With this method, we pull nanofur out of flat polymer films, and thus, tune its wettability from hydrophilic to super-hydrophobic. Moreover, we utilize the nanofur for oil/water separation and the cleaning up of oil spills.

News Archive

December 2024: Saumaun successfully defended his PhD thesis. Congratulations Dr. Reza!
December 2024: Patrick's final exam of his PhD took place and he passed successfully. Congratulations Dr. Weiser!
October 2024: Junchi successfully defended his PhD thesis "Quantum-Dot-Based Optoelectronics for Spectral Conversion". Congratulations Dr. Chen!
March 2024: Aiman defended his PhD thesis "Self-cleaning and Anti-Reflective Microtextured Fluoropolymer Cover Films for Photovoltaics" with great success. Congratulations Dr. Roslizar!
October 2023: Luisa successfully defended her PhD thesis "Bio-inspired white porous polymers fabricated via supercritical CO2 foaming". Congratulations Dr. Borgmann!
Summer 2023: Christian D'Ambrosio and Gonzalo Urquía from the University of Buenos Aires visited our group the support of the DAAD and their home university. Our joined research was published in an article in Optics Express 21, 20366 (2023)
Summer 2022: The documentary on butterflies "Schmetterlinge - Eine Quelle der Inspiration" (Butterflies - A Source of Inspiration) produced by the TV Station ARTE includes our research on transparent butterflies.
September 2020: Weibin's final exam of his PhD thesis "Tribological characterization of reptile scales and their application as technical surfaces with tunable friction anisotropy" took place and he passed successfully despite of the COVID19 conditions. Congratulations Dr. Wu!
August 2020: We published a summary of our work on foamed polymer foils as replacement for TiO2 and got some nice response. Please see the news on the KIT web-page.
February 2019: Christian's recent work on lambda-shaped carbon nanofibers is published in Small and got a nice cover page.
December 2018: Christian successfully passed the final exam of his PhD thesis "Bio-inspired dry adhesives from carbon nanofibers and their potential use in space technology". Congratulations Dr. Lutz!
November 2018: Radwanul H. Siddique, Yidenekechaw J. Donie, and Guillaume Gomard were awarded with the International Bionic Award 2018 for their work on the black butterffly Pachliopta aristolochiae. Congratulations for this big international honor. The original work is reported in an article in Science Advances and a KIT press release.
June 2018: Claudia Zeiger finished her Ph.D. thesis "Biomimetics for Efficient Oil Water Separation: From Natural Oil Sorbents to Bioinspired Micro- and Nanostructured Polymeric Sorbents and Membranes" and passed the final exams very sucessfully. Congratulations Dr. Zeiger!
June 2018: Our recent work on bio-inspired white films and oil-water separation is highlighted in two articles (structural colors & oil-spill cleanup) in Chemistry World.
May 2018: Felix Vüllers completed his Ph.D. thesis "Bioinspired Superhydrophobic Nano- and Microstructured Surfaces for Drag Reduction and Optoelectronics" and finished the final exam with great success. Congratulations Dr. Vüllers!
April 2018: Claudia's study on oil spill clean up with Salvinia leaves is highlighted in a podcast of Physics World.
October 2017: Radwan's, Donie's, and Guillaume's work on the bio-inspired improvemet of solar cells got published in Science Advances and is featured in a KIT press release.
September 2017: Senta Schauer successfully finished her Ph.D. thesis "Shape Memory Polymers for Bioninspired, Tunable Photonic Structure" and passed the final exam with honors. Congratulations Dr. Schauer!
June 2017: Senta's paper on surface wrinkles produced with the help of shape memory polymers got a nice cover page. Please have a look.
Mai 2017: We co-organized the 644. WE-Heraeus-Seminar on "Bio-inspired, Nano- and Microstructured Surfaces: New Functionality by Material and Structure" which was kindly sponosred by the WE-Heraeus Foundation. Please see the group photo.
November 2016: Radwan's study on the blue tarantula is featured in a press release of KIT and an interview with Radwan on ResearchGate.
August 2016: The study of Claudia exploring the oil clean-up with aquatic ferns is published in the journal Bioinspiration & Biomimetic. Please see the press release of KIT about this study.
August 2016: Our work on tailored AFM tips is featured in Applied Physics Letters and the KIT published a press release about it.
February 2016: Radwanul Hasan Siddique passed the final exam of his Ph.D. thesis "Structural Colors of Butterflies: Analysis and Fabrication of Bio-inspired Nanophotonic Surfaces" and finished with honors. Congratulations Dr. Siddique!
January 2016: We are co-organisers of the Symposium BM6 – Fabrication Characterization and Applications of Bioinspired Nanostructured Materials at the 2016 MRS Fall Meeting & Exhibit taking place in Boston, MA, November 27 – December 2, 2016
October 2015: Radwanul H. Siddique's research is advertised as a success story on the web-page of the KSOP.
July 2015: Our research on biomimetic nano- and microstructures is described in a podcast of "Welt der Physik" (in German). Please follow this link to listen to it.
Juni 2015: Donie Yidenekachew won the best poster award at the IONS conference in Karlsruhe with his contribution "Bio-inspired Black Butterfly’s Wing Nanostructures for Absorption Enhancement in Solar Cells"
April 2015: The study on the glasswing butterfly (Greta oto) of Radwanul H. Siddique got published in Nature Communications and the KIT published a press release about it.
July 2014: Radwanul H. Siddique's talk at the IONS15 conference won the best Oral Presentation award!
June 2014: The Ph.D. thesis "Fabrication and Analysis of Bio-Inspired Smart Surfaces" of Dr. Michael Röhrig was awarded with the "Dr.-Ing. Willy-Höfler-Doktorandenpreis" for the best dissertation in 2013 in the Mechanical Engineering Department of the KIT! Congratulations, Michael! And all the best for your future work.
Mai 2014: Tobias Meier successfully finished his Ph.D. study "Magnetoresistive and Thermoresistive Scanning Probe Microscopy With Applications in Micro- and Nanotechnology" and passed the final exam with great success. Congratulations Dr. Meier!
Mai 2014: Claudia Zeiger received a scholarship from the ZEISS Foundation supporting here Ph.D. study "Oil/Water separation utilizing biomimetic nanofur from biodegradable polymers for the cleaning of oil spills". Congratulations for this great success!