TY - JOUR A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - 1-Propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (Solarpur®) analyzed by hard x-ray photoelectron spectroscopy JF - Surface Science Spectra N2 - 1-Propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (Solarpur®), an ionic liquid was purchased from Merck (formerly Sigma Aldrich), was analyzed using hard x-ray photoelectron spectroscopy (HAXPES). The liquid is UHV stable, vertically and laterally homogeneous, and is easy to clean; thus, it can be used as a reference material. The HAXPES spectra of Solarpur® obtained using monochromatic Cr Kα radiation at 5414.8 eV include a survey scan, high-resolution spectra of C 1s, O 1s, N 1s, S 2p, S 1s, S 2s, F 1s, and S KLL. KW - HAXPES KW - Hard x-ray photoelectron spectroscopy KW - Ionic liquid KW - Solarpur PY - 2021 DO - https://doi.org/10.1116/6.0001414 VL - 28 IS - 2 SP - 1 EP - 8 PB - AVS: Science & Technology of Materials, Interfaces, and Processing AN - OPUS4-54113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radnik, Jörg A1 - Knigge, Xenia A1 - Andresen, Elina A1 - Resch-Genger, Ute A1 - Cant, D.J.H. A1 - Shard, A.G. A1 - Clifford, C.A. T1 - Composition, thickness, and homogeneity of the coating of core–shell nanoparticles—possibilities, limits, and challenges of X-ray photoelectron spectroscopy JF - Analytical and Bioanalytical Chemistry N2 - Core–shell nanoparticles have attracted much attention in recent years due to their unique properties and their increasing importance in many technological and consumer products. However, the chemistry of nanoparticles is still rarely investigated in comparison to their size and morphology. In this review, the possibilities, limits, and challenges of X-ray photoelectron spectroscopy (XPS) for obtaining more insights into the composition, thickness, and homogeneity of nanoparticle coatings are discussed with four examples: CdSe/CdS quantum dots with a thick coating and a small core; NaYF4-based upconverting nanoparticles with a large Yb-doped core and a thin Er-doped coating; and two types of polymer nanoparticles with a poly(tetrafluoroethylene) core with either a poly(methyl methacrylate) or polystyrene coating. Different approaches for calculating the thickness of the coating are presented, like a simple numerical modelling or a more complex simulation of the photoelectron peaks. Additionally, modelling of the XPS background for the investigation of coating is discussed. Furthermore, the new possibilities to measure with varying excitation energies or with hard-energy X-ray sources (hard-energy X-ray photoelectron spectroscopy) are described. A discussion about the sources of uncertainty for the determination of the thickness of the coating completes this review. KW - X-ray spectroscopy KW - Nanoparticles KW - Spectroscopy / Instrumentation KW - Spectroscopy / Theory PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548305 DO - https://doi.org/10.1007/s00216-022-04057-9 VL - 414 IS - 15 SP - 4331 EP - 4345 PB - SpringerNature AN - OPUS4-54830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Topolniak, Ievgeniia A1 - Elert, Anna Maria A1 - Knigge, Xenia A1 - Ciftci, G. C. A1 - Radnik, Jörg A1 - Sturm, Heinz T1 - High precision micropatterning of polydopamine by Multiphoton Lithography JF - Advanced Materials N2 - Mussel-inspired polydopamine (PDA) initiated a multifunctional modification route that leads to the generation of novel advanced materials and their applications. However, existing PDA deposition techniques still exhibit poor spatial control, have a very limited capability of micropatterning and do not allow to locally tune PDA topography. Herein, we demonstrate PDA deposition based on Multiphoton Lithography (MPL) that enables full spatial and temporal control with nearly total freedom of patterning design. Using MPL, we achieve 2D microstructures of complex design with pattern precision of 0.8 μm without the need of a photomask or stamp. Moreover, this approach permits adjusting the morphology and thickness of the fabricated microstructure within one deposition step, resulting in a unique tunability of materials properties. The chemical composition of PDA is confirmed and its ability for protein enzyme immobilization is demonstrated. This work presents a new methodology for high precision and complete control of PDA deposition, enabling PDA incorporation in applications where fine and precise local surface functionalization is required. Possible applications include multicomponent functional elements and devices in microfluidics or lab-on-a-chip systems. KW - Multiphoton lithography KW - Polydopamine KW - Micropatterning PY - 2022 DO - https://doi.org/10.1002/adma.202109509 VL - 34 IS - 18 SP - e2109509 PB - Wiley online library AN - OPUS4-54535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knigge, Xenia A1 - Guo, Z. A1 - Valsami-Jones, E. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Influence of Sterilization on the Surface of Nanoparticles Studied with XPS / HAXPES in Comparison to SEM / EDS JF - Microscopy and Microanalysis N2 - Nanosafety is becoming increasingly important as nanomaterials are widely used in industrial processes and consumer products. For nanotoxicity measurements prior sterilization of the samples is necessary, but as structure activity relationships are made with properties of pristine particles, the question arises, if the sterilization process has an impact on the physico-chemical properties of nanoparticles and thus on the biological behavior. This question will be addressed in this talk. For this purpose, results from SEM and EDS measurements are combined with those of a novel lab-based HAXPES spectrometer in order to obtain a more complete picture. At the end, an influence of sterilization will be evident, which indicates a restructuring of the nanoparticles owing to sterilization. T2 - Microscopy & Microanalysis 2022 CY - Portland, USA DA - 31.07.2022 KW - XPS KW - HAXPES KW - SEM KW - EDS KW - Nanoparticles PY - 2022 DO - https://doi.org/10.1017/S1431927622004287 VL - 28 SP - 986 EP - 988 PB - Cambridge University Press AN - OPUS4-55352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Häusler, I. A1 - Knigge, Xenia A1 - Hodoroaba, Vasile-Dan A1 - Emmerling, Franziska A1 - Reiss, P. A1 - Resch-Genger, Ute T1 - One-Pot Heat-Up Synthesis of ZnSe Magic-Sized Clusters Using Thiol Ligands JF - Inorganic Chemistry N2 - The synthesis of two new families of ZnSe magic-sized clusters (MSCs) is achieved using the thiol ligand 1-dodecanethiol in a simple one-pot heat-up approach. The sizes of the MSCs are controlled with the thiol ligand concentration and reaction temperature. KW - ZnSe KW - Magic-sized cluster KW - Dodecanethiol KW - Semiconductor nanocrystals KW - One-pot synthesis PY - 2022 DO - https://doi.org/10.1021/acs.inorgchem.2c00041 VL - 61 IS - 19 SP - 7207 EP - 7211 PB - ACS Publications CY - Washington, DC (USA) AN - OPUS4-54880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - 1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES JF - Surface Science Spectra N2 - The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy. Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown. KW - C7H15N2O4P KW - [MMIM]+[DMP]− KW - Lonic liquid KW - Hard x-ray photoelectron spectroscopy KW - HAXPES KW - XPS PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571604 DO - https://doi.org/10.1116/6.0002297 VL - 30 IS - 1 SP - 1 EP - 20 PB - AIP Publishing AN - OPUS4-57160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Kai A1 - Mirabella, Francesca A1 - Knigge, Xenia A1 - Mezera, Marek A1 - Weise, Matthias A1 - Sahre, Mario A1 - Wasmuth, Karsten A1 - Voss, Heike A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Chemical and topographical changes upon sub-100-nm laser-induced periodic surface structure formation on titanium alloy: the influence of laser pulse repetition rate and number of over-scans JF - Physica Status Solidi A N2 - Titanium and its alloys are known to allow the straightforward laser-based manufacturing of ordered surface nanostructures, so-called high spatial frequency laser-induced periodic surface structures (HSFL). These structures exhibit sub-100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi-method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near-surface chemical analyses hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (ToF-SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non-ablative laser-induced near-surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat-accumulation effects. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Laser processing KW - Hard X-ray photoelectron spectroscopy (HAXPES) KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589902 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.202300719 DO - https://doi.org/10.1002/pssa.202300719 SN - 1862-6319 VL - 220 SP - 1 EP - 12 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chemello, Giovanni A1 - Knigge, Xenia A1 - Ciornii, Dmitri A1 - Reed, B.P. A1 - Pollard, A.J. A1 - Clifford, C.A. A1 - Howe, T. A1 - Vyas, N. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Influence of the Morphology on the Functionalization of Graphene Nanoplatelets Analyzed by Comparative Photoelectron Spectroscopy with Soft and Hard X-Rays JF - Advance Materials Interfaces N2 - Since its isolation, graphene has received growing attention from academia and industry due to its unique properties. However, the “what is my material” barrier hinders further commercialization. X-ray photoelectron spectroscopy (XPS) is considered as a method of choice for the determination of the elemental and chemical composition. In this work the influence of the morphology of graphene particles on the XPS results is studied and investigated as a function of X-ray energy, using conventional XPS with Al K𝜶 radiation and hard X-ray photoemission spectroscopy (HAXPES) using Cr K𝜶 radiation. Thereby, the information depth is varied between 10 and 30 nm. For this purpose, two commercial powders containing graphene nanoplatelets with lateral dimensions of either ≈100 nm or in the micrometer range are compared. These larger ones exist as stack of graphene layers which is inspected with scanning electron microscopy. Both kinds of particles are then functionalized with either oxygen or fluorine. The size of the graphene particles is found to influence the degree of functionalization. Only the combination of XPS and HAXPES allows to detect the functionalization at the outermost surface of the particles or even of the stacks and to provide new insights into the functionalization process. KW - Functionalized graphene KW - Hard-energy X-ray photoelectron spectroscopy KW - X-ray photoelectron spectroscopy PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578860 DO - https://doi.org/10.1002/admi.202300116 SN - 2196-7350 SP - 1 EP - 8 PB - Wiley VCH AN - OPUS4-57886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Božičević, Lucija A1 - Altmann, Korinna A1 - Hildebrandt, Jana A1 - Knigge, Xenia A1 - Vrček, Valerije A1 - Peranić, Nikolina A1 - Kalcec, Nikolina A1 - Vinkovic Vrcek, Ivana T1 - Estrogenic activity of plastic nanoparticles mixture under in vitro settings JF - Environmental Science: Nano N2 - The plastic value chain, central part of modern living, caused environmental pollution and bioaccumulation of plastic nanoparticles (PNPs). Their ubiquitous presence in different environmental and biological compartments has become a serious threat to human health and ecosystems. Frequently used plastic materials such as polypropylene (PP), polystyrene (PS) and polyethylene (PE) have been detected in the form of PNPs in the food chain, soil, water and air, as well as in human feces and blood. In this study, we aimed to provide novel insights in endocrine disrupting properties of PNPs using in vitro estrogen receptor (ER) transactivation assay. The effects of PP-NPs, PE-NPs and PS-NPs and their mixture on T47D-KBluc cell line stably transfected with luciferase as reporter enzyme was evaluated by means of cytotoxicity, cellular uptake and ER activation. Tested dose range for PNPs was 0.001 – 10 mg/L. Both cellular uptake and cytotoxicity for all PNPs was found to be dose-dependent. Only the highest dose of PP-NPs and PE-NPs induced apoptosis and cell death, while PS-NPs were not cytotoxic in tested dose range. For tested concentrations, PP-NPs and PE-NPs showed significant agonistic activity on ER, while PS-NPs cannot be considered ER active. When, applied as mixture, PNP demonstrated additive toxicity effects compared to the effect of each individual PNPs. Additivity was also observed for ER agonistic effect of PNPs mixture according to the benchmark dose-addition modelling approach. This study provides missing science-based evidence on endocrine disrupting effects of PE-NPs, PP-NPs, PS-NPs and their mixtures and highlights the importance of considering unintentional, aggregate and combined exposure to different PNPs in risk management. KW - Risk assessment KW - Nanoplastics KW - Estrogenic activity of plastic nanoparticles PY - 2024 DO - https://doi.org/10.1039/D3EN00883E SN - 2051-8153 VL - 11 IS - 5 SP - 2112 EP - 2126 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voss, Heike A1 - Knigge, Xenia A1 - Knapic, D. A1 - Weise, Matthias A1 - Sahre, Mario A1 - Hertwig, Andreas A1 - Sacco, A. A1 - Rossi, A. M. A1 - Radnik, Jörg A1 - Müller, Kai A1 - Wasmuth, Karsten A1 - Krüger, Jörg A1 - Hassel, A. W. A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Picosecond laser processing of hierarchical micro–nanostructures on titanium alloy upon pre- and postanodization: morphological, structural, and chemical effects JF - Physica Status Solidi A N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone-forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre- and postanodization for two different characteristic microspikes covered by nanometric laser-induced periodic surface structures on Ti–6Al–4V upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X-ray diffraction, and micro-Raman spectroscopy, as well as near-surface chemical analyses by X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near-surface oxidation that may affect the different cell growth behavior for pre- or postanodized medical implants. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Hierarchical micro-nanostructures KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Ti-6Al-4V alloy KW - X-ray photoelectron spectroscopy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601962 DO - https://doi.org/10.1002/pssa.202300920 SN - 1862-6319 SP - 1 EP - 11 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-60196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -