TY - CONF A1 - Thünemann, Andreas T1 - Nanoplastics Aqueous Dispersions as Polymer Reference Materials for a Sustainable Future N2 - The undesirable presence of micro and nanoplastics in our environment and in food is now common knowledge. However, it is unclear whether serious dangers and risks are posed by nanoplastics. A scientifically based reliable determination of the type and quantity of nanoplastics in complex matrices is of considerable importance for the future sustainable use of polymers. Here, reference materials help in the determination of nanoplastics. In particular, colloidally stable aqueous dispersions of nanoplastics appear suitable for this purpose. We report on the current status of the development of nanoplastics as reference materials. A detailed example of reference materials for characterizing nanoplastics is provided in the form of aqueous dispersion of polypropylene. The nanoplastics samples are colloidal stable for at least two years at ambient conditions. A low zeta potential of -35 mV at a neutral pH value provides stability. An overview of their colloidal properties in different environmental conditions is presented. Next, polyethylene nanoplastics will be compared to polypropylene nanoplastics. Nanoplastics consisting of poly(ethylene terephthalate) will be discussed and finally, we report on poly(L-lactic acid) as a typical and important representative of biodegradable polymers. T2 - POLYMERS FOR A SUSTAINABLE FUTURE: Biennial Meeting of the GDCh-Division of Macromolecular Chemistry CY - Dresden, Germany DA - 16.09.2024 KW - Reference Material PY - 2024 AN - OPUS4-61079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Quantifying the Total and Accessible Number of Surface Functional Groups and Ligands on Engineered Nanomaterials Using a Multimodal Approach N2 - Functionalized nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing, electronics or food and consumer products. For instance, NMs are used as drug carriers, fluorescent sensors, and multimodal labels in bio-analytical assays and imaging applications. The performance and safety of NMs are influenced by their intrinsic physicochemical properties. Among these, the surface chemistry of the particles, which is largely determined by the chemical nature and density of functional groups and ligands, plays a crucial role in enhancing the stability, and processability of NMs, as well as their interactions with the environment. Thus, particle standards with well-designed surfaces and methods for functional group quantification can foster the sustainable development of functional and safe(r) NM.[1] To develop simple, versatile, and multimodal tools for quantifying various bioanalytically relevant functional groups (FG) such as amine,[2,3] carboxy,[2] thiol, and aldehyde[4] functionalities, we explored and compared several analytical methods. These methods included electrochemical titration, dye-based optical assays, and other instrumental techniques like nuclear magnetic resonance, mass spectrometry, and thermal analysis. Our multimodal approach’s potential for FG quantification was demonstrated using both commercial and custom-made polymeric and silica particles with different densities of functional groups. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Quality Assurance KW - Nano Particle KW - qNMR KW - Potentiometry KW - Reference Material KW - Surface Analysis KW - Advance Materials KW - Functional Group KW - Silica KW - Synthesis KW - Optical Assays KW - Reference Data PY - 2025 AN - OPUS4-65000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stockmann, Jörg M. T1 - Reference material for the determination of the field of view of small-area X-ray photoelectron spectrometers N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces. For evaluating the quality of such microstructures, it is crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. The aperture has a major influence on the signal-contribution from the outside. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize the FoV: The signal-contribution from the outside is reduceable down to lower than 50 %, when the aperture is 30 % of the structure dimension for our Kratos AXIS Ultra DLD system. T2 - Kratos User's Meeting 2020 CY - Online meeting DA - 21.09.2020 KW - Small-area XPS KW - Field of View KW - Imaging XPS KW - Reference Material PY - 2020 AN - OPUS4-51412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Maxi B. A1 - Böhmert, Linda A1 - Thünemann, Andreas A1 - Loeschner, Katrin A1 - Givelet, Lucas A1 - Fahrenson, Christoph A1 - Braeuning, Albert A1 - Sieg, Holger T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles. KW - Toxicology KW - Nanoparticles KW - Dynamic Light Scattering KW - Nanoplastics KW - Microplastics KW - Reference Method KW - Reference Material PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947 DO - https://doi.org/10.1016/j.fct.2023.114423 SN - 0278-6915 VL - 184 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-59394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hildebrandt, Jana A1 - Thünemann, Andreas T1 - Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics N2 - Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D h = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of 𝜻 = −43 ± 2 mV. KW - Nanoparticles KW - Reference Material KW - Nanoplastics PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571799 DO - https://doi.org/10.1002/marc.202200874 SN - 1022-1336 VL - 44 IS - 6 SP - 1 EP - 15 PB - Wiley-VCH CY - Weinheim AN - OPUS4-57179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Reliable analysis of the elemental composition of graphene oxide flakes with energy dispersive spectroscopy (SEM/EDS) and x-ray photoelectron spectroscopy (XPS) N2 - Suspensions of graphene-related 2D materials (GR2M) are broadly used for further applications like printable electronics. The reliable quantification of the composition of graphene-related 2D materials as liquid suspensions is still a challenging task, which can hinder the commercialisation of the products. Specific parameters to be measured are defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1], but reference protocols are still missing. One of the central methods for the quantification is X-ray photoelectron spectroscopy (XPS) as a rather expensive method. Therefore, the development of cheaper alternatives is highly desired. One attractive alternative of XPS is energy-dispersive spectroscopy (EDS) which is usually coupled with scanning electron microscopy (SEM). This combination is one of the most widely used methods in analytical laboratories. In this contribution the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [3], which has been carried out on the same samples. It is demonstrated that for samples prepared by drop-casting on a substrate, both surface-sensitive XPS analysis and bulk-characterising EDS result in very similar elemental composition of oxygen and carbon for thick spots. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. The last results clearly show the influence of the substrate on the analysis of the results and stressed out the importance of the sample preparation. T2 - E-MRS Spring Meeting CY - Strasbourg, France DA - 26.05.2025 KW - Graphene oxide KW - Reliable Analysis KW - Ionic Liquid KW - Reference Material PY - 2025 AN - OPUS4-63336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -