TY - JOUR A1 - Fornacon-Wood, Christoph A1 - Stühler, Merlin R. A1 - Millanvois, Alexandre A1 - Steiner, Luca A1 - Weimann, Christiane A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Paulus, Beate A1 - Plajer, Alex J. T1 - Fluoride recovery in degradable fluorinated polyesters N2 - We report a new class of degradable fluorinated polymers through the copolymerization of tetrafluorophthalic anhydride and propylene oxide or trifluoropropylene oxide which show up to 20 times quicker degradation than the non-fluorinated equivalents and allow for fluoride recovery. KW - Fluoropolymers KW - Recycling KW - PFAS KW - AFM force distance curves KW - AFM plastic deformation KW - AFM friction analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606768 DO - https://doi.org/10.1039/d4cc02513j VL - 60 SP - 7479 EP - 7482 PB - Royal Society of Chemistry AN - OPUS4-60676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waegner, M. A1 - Schröder, M. A1 - Suchaneck, G. A1 - Sturm, Heinz A1 - Weimann, Christiane A1 - Eng, L. M. A1 - Gerlach, G. T1 - Enhanced piezoelectric response in nano-patterned lead zirconate titanate thin films N2 - In this work, Pb(Zr,Ti)O3 thin films were used to fabricate well-ordered nanodot arrays by means of nanosphere lithography. This technique is based on a two-step etch process that enables excellent control of the fabrication of ordered nanodisc arrays of defined height, diameter, and pitch. Piezoresponse force microscopy was used to investigate both non-patterned and patterned films. The topography and both the out-of-plane and the in-plane polarization were deduced in this mode. Grains of nanodots with a low aspect ratio form domain structures comparable to domains in non-patterned two-dimensional films. In contrast, nanodots with a higher aspect ratio form particular structures like bi-sectioned domain assemblies, c-shaped domains or multi-domains surrounding a center domain. The patterning of the ferroelectric material was shown to affect the formation of ferroelectric domains. The initial polycrystalline films with random polarization orientation re-orient upon patterning and then show domain structures dependent on the nanodisc diameter and aspect ratio. KW - Nanostructures KW - Ferroelectric KW - Nanodots PY - 2012 DO - https://doi.org/10.1143/JJAP.51.11PG04 SN - 0021-4922 VL - 51 SP - 1 EP - 5 PB - IOP Publ. CY - Bristol AN - OPUS4-27697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Heinz A1 - Schröter, Maria-Astrid A1 - Weimann, Christiane T1 - Imaging method for vibrating scanning force microscopy cantilevers for the analysis of mode shapes and nonlinear harmonic motion N2 - A specially designed scanning force microscope (SFM, atomic force microscope – AFM) was incorporated into the chamber of a commercial scanning electron microscope (SEM) to investigate vibrating SFM cantilevers at their resonance. Inherently, the spatial resolution of electron microscopy is higher than that of optical methods. In this paper we present vibration modes (eigenmodes) of two different SFM cantilevers. Their nonlinear behavior is also explored in order to depict their 2nd harmonics (twice the fundamental frequency). Imaging of the local vibration is performed by measuring the frequency- and phase-selective responses of the SE signal at different X and Y positions of the scanned electron beam. KW - Electron microscopy KW - Scanning force microscopy KW - Motion detection KW - Cantilever KW - Eigenmode KW - Harmonic KW - Nonlinearity KW - Harmonix cantilever PY - 2012 DO - https://doi.org/10.1016/j.mee.2012.07.088 SN - 0167-9317 SN - 1873-5568 VL - 98 SP - 492 EP - 496 PB - Elsevier Science CY - Amsterdam, Netherlands AN - OPUS4-26431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Pauw, Brian Richard A1 - Weimann, Christiane A1 - Sturm, Heinz T1 - First of its kind: A test artifact for direct laser writing N2 - With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate the high geometrical resolution of fs-LDW structures and the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement. KW - Laser direct writing KW - Multi photon lithography KW - Reference material KW - Raman spectroscopy KW - Confocal raman imaging KW - Slicers KW - Open data on zenodo PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580951 DO - https://doi.org/10.1088/1361-6501/acc47a VL - 34 IS - 7 SP - 1 EP - 14 PB - IOP Science AN - OPUS4-58095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Lorenz, Edelgard A1 - Weimann, Christiane A1 - Sturm, Heinz A1 - Karimov, I. A1 - Ettl, J. A1 - Meier, R. A1 - Wohlgemuth, W. A. A1 - Berger, H. A1 - Wildgruber, M. T1 - Mechanic and surface properties of central-venous port catheters after removal: A comparison of polyurethane and Silicon rubber materials N2 - Central venous port devices made of two different polymeric materials, thermoplastic polyurethane (TPU)and silicone rubber (SiR), were compared due their material properties. Both naïve catheters as well as catheters after removal from patients were investigated. In lab experiments the influence of various chemo-therapeutic solutions on material properties was investigated, where as the samples after removal were compared according to the implanted time inpatient. The macroscopic,mechanical performance was assessed with dynamic, specially adapted tests for elasticity. The degradation status of the materials was determined with common tools of polymer characterisation, such as infrared spectroscopy, molecular weight measurements and various methods of thermal analysis. The surface morphology was an alysed using scanning electron microscopy. A correlation between material properties and clinical performance was proposed. The surface morphology and chemical composition of the polyurethane catheter materials can potentially result in increased susceptibility of the catheter to bloodstream infections and thrombotic complications. The higher mechanic failure,especially with increasing implantation time of the silicone catheters is related to the lower mechanical performance compared to the polyurethane material as well as loss of barium sulphate filler particles near the surface of the catheter. This results in preformed microscopic notches, which act as predetermined sites of fracture. KW - Thermoplastic polyurethane (TPU) KW - Silicone rubber (SiR) KW - Catheters KW - Central venous access port KW - Complication KW - Structure propertyrelationship KW - Mechanical testing PY - 2016 DO - https://doi.org/10.1016/j.jmbbm.2016.08.002 SN - 1751-6161 SN - 1878-0180 VL - 64 SP - 281 EP - 291 PB - Elsevier Ltd. AN - OPUS4-37178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wimmer, L A1 - Hoang, M V N A1 - Schwarzinger, J A1 - Jovanovic, V A1 - Adelkovic, B A1 - Velickovic, T C A1 - Meisel, T C A1 - Waniek, T A1 - Weimann, Christiane A1 - Altmann, Korinna A1 - Dailey, L A T1 - A quality-by-design inspired approach to develop PET and PP nanoplastic test materials for use in in vitro and in vivo biological assays N2 - Micro- and nanoplastics have become environmental pollutants of concern, receiving increased attention from consumers, scientists, and policymakers. The lack of knowledge about possible impacts on wildlife and human health requires further research, for which well-characterized testmaterials are needed. A quality-bydesign (QbD) driven approachwas used to produce sterile, endotoxinmonitored nanoplastics of polyethylene terephthalate (PET) and polypropylene (PP) with a size fraction of >90% below 1 μm and high yield of >90%. Glycerol was used as a versatile and biocompatible liquid storage medium which requires no further exogenous dispersing agent andmaintained colloidal stability, sterility (0 CFU mL−1), and low endotoxin levels (<0.1 EU mL−1) for more than one year of storage at room temperature. Further, the glycerol vehicle showed no biological effect on the tested human bronchial cell line Calu-3 up to 0.8% (w/v). Given the concentration of 40 mg g−1 nanoplastics in the glycerol stock, this corresponds to a nanoplastic concentration of 320 μg mL−1. The surfactant-free nanoplastics are dispersible in bio-relevant media from the glycerol stock without changing size characteristics and are suitable for in vitro and in vivo research. KW - Microplastics KW - Reference materials KW - Nanoplastics KW - Polymer 3R KW - Glycerol PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629934 DO - https://doi.org/10.1039/D4EN01186D SN - 2051-8161 VL - 12 IS - 5 SP - 2667 EP - 2686 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-62993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -