TY - JOUR A1 - Probst, Anne-Catherine A1 - Stollenwerk, Manfred A1 - Emmerich, Florian A1 - Büttner, Andre A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Riethmüller, Franziska A1 - Stehlikova, Veronika A1 - Mingwu, Wen A1 - Proserpio, Laura A1 - Damm, Christine A1 - Rellinghaus, Bernd A1 - Döhring, Thorsten T1 - Influence of sputtering pressure on the nanostructure and the X-ray reflectivity of iridium coatings JF - Surface and Coatings Technology N2 - Reflective mirror coatings made of iridium are used in X-ray telescopes of the Chandra X-ray Observatory (CXO) launched in 1999 by the National Aeronautics and Space Administration (NASA) to investigate astronomical sources at photon energies below 10. keV. These coatings were produced in a DC magnetron sputtering process and have so far proven their suitability for space-based applications. We are considering in the present paper the processing of thin iridium films for lightweight telescopes using the radio frequency magnetron sputtering technique with an oblique angle deposition. The coating development presented here is focused on the influence of total sputtering pressure on film properties as well as on its impact on the mirror's performance. Characterisation methods such as X-ray diffractometry, X-ray reflectometry, atomic force microscopy and transmission electron microscopy have been used. Correlations between morphology, density, surface micro-roughness, crystal structure of the iridium layer and the expected reflectivity of the X-ray mirror are described and discussed. KW - Iridium KW - sputtering KW - microstructure KW - coating KW - X-ray KW - Iridium KW - Röntgenteleskop Y1 - 2017 UR - https://doi.org/10.1016/j.surfcoat.2017.10.062 SN - 0257-8972 VL - 2017 IS - 343 SP - 101 EP - 107 ER - TY - CHAP A1 - Khropost, Diana A1 - Riethmüller, Franziska A1 - Stanik, Eva A1 - Döhring, Thorsten A1 - Hertwig, Andreas A1 - Huelague, Deniz T1 - Polydopamine – a bionic material and its potential applications for batteries T2 - MaterialsWeek 2025 – Book of Abstracts N2 - Polydopamine (PDA) recently came into focus as an innovative material for applications in various technical fields, especially in the energy field it is considered for batteries as well as for supercapacitors. It is a very strong glue that sticks on almost everything, even under water: In nature, PDA is found in the byssal thread cuticles of mussels. The wet-resistant adhesion ability of PDA can be used in the treatment of separator membranes in batteries, but furthermore PDA is also considered as an electrode material for batteries. We have investigated thin layers of poly-dopamine with different methods including ellipsometry, tactile measurements of the layer thickness and in situ absorption measurements during the polymerization process. KW - polydopamine KW - PDA KW - bionic material KW - adhesion KW - absorption KW - Iridium KW - Katalysator KW - Wasserstoffenergietechnik Y1 - 2025 SN - 978-3-88355-446-4 SP - 67 EP - 67 PB - Deutsche Gesellschaft für Materialkunde e.V. (DGM) CY - Sankt Augustin ER - TY - CHAP A1 - Khropost, Diana A1 - Riethmüller, Franziska A1 - Döhring, Thorsten A1 - Flachs, Dennis A1 - Hülagü, Deniz A1 - Hertwig, Andreas A1 - Cotroneo, Vincenzo A1 - Gibertini, Eugenio ED - Hudec, René ED - Pina, Ladislav T1 - Polydopamine: a bio-inspired polymer for X-ray mirror coatings and other technical applications T2 - EUV and X-ray Optics: Synergy between Laboratory and Space IX N2 - Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as one of the “hormones of happiness”, thin polymer films of polydopamine (PDA) also have interesting technical properties. PDA is a very strong glue that sticks on almost everything, even under water. In nature, PDA is found in the byssal thread cuticles of mussels. When produced by dip-coating, the self-organizing PDA layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometres thickness only. Here we present an optimized preparation regime as derived from polymerization analysis through absorption spectroscopy. One application is the use of thin PDA overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. Furthermore, we give an outlook to other technical applications for this interesting material, presenting this bio-inspired organic polymer as an innovative technical solution for the future, with applications such as PDA-based super-capacitors and its promising role in enhancing separator materials for batteries. KW - polydopamin KW - ellipsometry KW - X-ray KW - battery KW - Röntgenspiegel KW - Beschichtung Y1 - 2025 U6 - https://doi.org/10.1117/12.3056298 VL - 2025 IS - 13531 SP - 135310H-1 EP - 135310H-11 PB - SPIE ER - TY - GEN A1 - Khropost, Diana A1 - Döhring, Thorsten A1 - Riethmüller, Franziska A1 - Hülagü, Deniz T1 - Poly-dopamine - an organic material for X-ray mirror coatings and other technical applications T2 - AXRO 2024 - 15th International Conference on Astronomical X-Ray Optics N2 - Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as the “hormone of happiness”, thin polymer films of poly-dopamine also have interesting technical properties. When produced by dip coating, these self-organizing layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometre thickness only. One application is the use of thin poly-dopamine overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. We thereby introduce a method of determining the layer thickness of poly-dopamine, which is based on spectroscopic ellipsometry measurements and applies an optical model for the poly-dopamine layers including their dielectric function. Furthermore, we give an outlook to other technical applications for this promising material, presenting this bio-inspired organic polymer as an innovative technical solution for the future. N2 - Poster KW - poly-dopamine KW - X-ray mirror KW - X-ray astronomy KW - ellipsometry KW - thin layers KW - Röntgenspiegel Y1 - 2024 VL - 2024 SP - 1 EP - 1 ER -