TY - CONF A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan T1 - Evaluation and selection of techniques and methodologies to support the implementation of the EC recommendation for a definition of nanomaterial T2 - Synergy Workshop NanoDefine with other NSC (Nano Safety Cluster) Projects CY - Copenhagen, Denmark DA - 2014-06-06 PY - 2014 AN - OPUS4-30958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Hodoroaba, Vasile-Dan A1 - Mielke, Johannes T1 - Templates for nanomaterial characterisation of tier 1 and tier 2 measurement methods N2 - The EU FP7 NanoDefine project was launched in November 2013 and will run until October 2017. The Project is dedicated to support the implementation of the EU Recommendation on the Definition of Nanomaterial by the provision of the required analytical tools and respective guidance. Main goal is to develop a novel tiered approach consisting of (i) rapid and cost-efficient screening methods and (ii) confirmatory measurement methods. The "NanoDefiner" eTool will guide potential end-users, such as concerned industries and regulatory bodies as well as enforcement and contract laboratories, to reliably classify if a material is nano or not. To achieve this objective, a comprehensive inter-laboratory evaluation of the performance of current characterisation techniques, instruments and software is performed. Instruments, software and methods are further developed. Their capacity to reliably measure the size of particulates in the size range 1-100 nm and above (according to the EU definition) is validated. Technical reports on project results are published to reach out to relevant stakeholders, such as policy makers, regulators, industries and the wider scientific community, to present and discuss our goals and results, to ensure a continuous exchange of views, needs and experiences obtained from different fields of expertise and application, and to finally integrate the resulting feedback into our ongoing work on the size-related classification of nanomaterials. KW - Nanomaterial KW - Measurement method KW - Screening methods KW - Confirmatory methods PY - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-389827 UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports SP - 1 EP - 74 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-38982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan T1 - The Project NanoDefine T2 - International summer workshop "NANOSCIENCE meets METROLOGY" CY - Erice, Italy DA - 2015-07-27 PY - 2015 AN - OPUS4-33892 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Ullmann, Ch. A1 - Babick, F. A1 - Weigel, St. T1 - Evaluation and Comparison of Particle Sizing Techniques within the EC/FP7 Project NanoDefine T2 - International summer workshop "NANOSCIENCE meets METROLOGY" CY - Erice, Italy DA - 2015-07-27 PY - 2015 AN - OPUS4-33893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, P. A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Kägi, R. A1 - Ryner, M. T1 - Assessment of different electron microscopy techniques for particle size quantification of potential nanomaterials N2 - While nano-scaled intermediate and consumer products are omnipresent in many industries, one challenge consists in the development of methods that reliably identify, characterize and quantify nanomaterials both as a substance and in various matrices. For product registration purposes, the European Commission proposed a definition for nanomaterial which requires a quantitative size determination of the primary particles in a sample down to sizes of 1 nm. According to a material is defined as nano if 50% of the primary particles are observed to comprise a smallest dimension <100 nm. The NanoDefine project was set up to develop and validate a robust, readily implementable and cost-effective measurement approach to obtain a quantitative particle size distribution and to distinguish between nano and non-nano materials according to the definition Among the available particle sizing techniques, electron microscopy was found to be one option meeting most of the requirements of the regulation. However, the use of electron microscopy for particle sizing is often limited by cost per sample, availability in industry, particle agglomeration/aggregation, extremely broad size distributions, 2D materials and operator bias in case of manual evaluation. PY - 2015 U6 - https://doi.org/10.1017/S1431927615012799 SN - 1431-9276 SN - 1435-8115 VL - 21 IS - Suppl. 3 SP - Paper 1200, 2403 EP - 2404 PB - Cambridge University Press CY - New York, NY AN - OPUS4-34922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Rades, Steffi A1 - Ortel, Erik A1 - Salge, T. A1 - Hodoroaba, Vasile-Dan T1 - Improved spatial resolution of EDX/SEM for the elemental analysis of nanoparticles N2 - The interest in nanoparticles remains at a high level in fundamental research since many years and increasingly, nanoparticles are incorporated into consumer products to enhance their performance. Consequently, the accurate and rapid characterization of nanoparticles is more and more demanded. Electron microscopy (SEM, TSEM and TEM) is one of the few techniques which are able to image individual nanoparticles. It was demonstrated recently that the transmission electron microscopy at a SEM can successfully be applied as a standard method to characterize accurately the size (distribution) and shape of nanoparticles down to less than 10 nm. PY - 2015 U6 - https://doi.org/10.1017/S1431927615009344 SN - 1431-9276 SN - 1435-8115 VL - 21 IS - Suppl. 3 SP - Paper 0855, 1713 EP - 1714 PB - Cambridge University Press CY - New York, NY AN - OPUS4-34923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Babick, F. A1 - Wohlleben, W. A1 - Ullmann, C. A1 - Hodoroaba, Vasile-Dan T1 - NanoDefine, Work package 3: The methods evaluation hub T2 - EuoNanoForum 2015 CY - Riga, Lativa DA - 2015-06-10 PY - 2015 AN - OPUS4-33401 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Rades, Steffi A1 - Ortel, Erik A1 - Wirth, Thomas A1 - Salge, T. A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan T1 - Advanced analytical scanning electron microscopy for the characterization of nanoparticles T2 - EuoNanoForum 2015 CY - Riga, Lativa DA - 2015-06-10 PY - 2015 AN - OPUS4-33402 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Babick, F. A1 - Ullmann, Ch. A1 - Hodoroaba, Vasile-Dan T1 - Evaluierung der Messmethoden zur Implementierung der EU-Empfehlung zur Definition von Nanomaterialien im Projekt "NanoDefine" T2 - Workshop von Bundesbehörden/VCI/VdMi "Messstrategien und Messmethoden für Nanomaterialien" CY - Berlin, Germany DA - 2015-09-08 PY - 2015 AN - OPUS4-34064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Salge, T. A1 - Mielke, Johannes A1 - Ortel, Erik A1 - Schmidt, R. T1 - Characterisation of nanoparticles by means of high-resolution SEM/EDS N2 - Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass - thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS. T2 - EMAS 2015 - 14th European workshop on modern developments and applications in microbeam analysis CY - Portoroz, Slovenia DA - 03.05.2015 KW - SEM KW - T-SEM KW - EDX KW - Nanoparticles KW - High-resolution PY - 2015 SN - 978-90-8227-691-6 U6 - https://doi.org/10.1088/1757-899X/109/1/012006 SP - NUR code:972 - Materials Science, 187-199 AN - OPUS4-33258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Hodoroaba, Vasile-Dan A1 - Mielke, Johannes T1 - Techniques evaluation report for selection of characterisation methods N2 - This report is the result of a comprehensive study on the available CMs which come potentially in question for the reliable analysis of the number based size distribution of a nanomaterial according to the EC recommendation for a definition of nanomaterial. Based on the performance criteria already established in NanoDefine the potential CMs are evaluated according to studies available in the literature as well as following the expertise of the NanoDefine consortium partners. The specific advantages and disadvantages of each method with respect to its applicability to the scope of NanoDefine are particularly highlighted. An CM evaluation table is produced so that the mostly suited CMs with respect to the EC definition can be grouped and recommended to the corresponding NanoDefine work packages for further specific development (improvement and adaption), or for direct validation and standardisation, respectively. The actual evaluation report including the recommended CMs will be revised and, if necessary, eventually updated at the mid time of the project. The update will be jointly discussed in the NanoDefine consortium on the basis of the results of testing the methods on the NanoDefine real world materials. KW - Nanomaterial KW - Characterization method KW - EC definition PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-389473 UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D3.1.pdf SP - D3.1, 1 EP - 57 CY - Wageningen, The Netherlands AN - OPUS4-38947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Hanke, F. A1 - Peters, M.V. A1 - Hecht, S. A1 - Persson, M. A1 - Grill, L. T1 - Adatoms underneath single porphyrin molecules on Au(111) N2 - The adsorption of porphyrin derivatives on a Au(111) surface was studied by scanning tunneling microscopy and spectroscopy at low temperatures in combination with density functional theory calculations. Different molecular appearances were found and could be assigned to the presence of single gold adatoms bonded by a coordination bond underneath the molecular monolayer, causing a characteristic change of the electronic structure of the molecules. Moreover, this interpretation could be confirmed by manipulation experiments of individual molecules on and off a single gold atom. This study provides a detailed understanding of the role of metal adatoms in surface–molecule bonding and anchoring and of the appearance of single molecules, and it should prove relevant for the imaging of related molecule–metal systems. PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-324144 UR - http://pubs.acs.org/doi/pdf/10.1021/ja510528x SN - 0002-7863 SN - 1520-5126 VL - 137 IS - 5 SP - 1844 EP - 1849 PB - American Chemical Society CY - Washington, DC AN - OPUS4-32414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rauscher, H. A1 - Mech, A. A1 - Gaillard, C. A1 - Stintz, M. A1 - Wohlleben, W. A1 - Weigel, St. A1 - Ghanem, A. A1 - Hodoroaba, Vasile-Dan A1 - Babick, F. A1 - Mielke, Johannes T1 - Recommendations on a Revision of the EC Definition of Nanomaterial Based on Analytical Possibilities N2 - In October 2011 the European Commission (EC) published a "Recommendation on the definition of nanomaterial" (2011/696/EU), to promote consistency in the interpretation of the term "nanomaterial" for legislative and policy purposes in the EU. The EC NM Definition includes a commitment to its review in the light of experience and of scientific and technological developments. This review is ongoing in 2015 and as a contribution to the review the Joint Research Centre of the European Commission (JRC) has already developed a series of three scientific-technical reports with the title: “Towards a review of the EC Recommendation for a definition of the term nanomaterial” which provides to the EC policy services science-based options on how the definition could be revised or supported with additional guidance. The overarching nature and wide scope of the EC NM Definition, as it does not exclude a priori any particulate material regardless the state, form and size, creates many analytical challenges in its imple-mentation for all stakeholders, including enterprises and regulators. The NanoDefine project has as core objective to support the implementation of the EC NM Definition. In this report key aspects of the EC NM Definition are addressed, with the goal to improve the implement-ability of the EC NM Definition. These aspects are presented and discussed based on the results of two years of research performed within the framework of the project. As a result this report assesses how well the requirements of the EC NM Definition can be fulfilled with currently available analytical possi-bilities. It presents recommendations and options on a revision of the EC NM Definition to improve the implementability of the definition based on currently available analytical possibilities, according to the state of the art of mid-2015. Of the technical issues considered in this report, the following seem to deserve the most attention in terms of clarification of the definition and/or provision of additional implementation guidance:  The term ‘external dimension’. A clear definition of 'External dimension' should be included in the text of the EC NM definition and more precise guidance on what is considered as an external dimension and how to properly character-ise it should be provided.  The ‘number based particle size distribution‘. The EC NM Definition uses a threshold related to the number based size distribution of particles. Yet most of the easily available techniques provide a mass-, volume- or scattered light intensity-based size distribution which needs to be converted into a number based distribution to be used for regulatory pur-poses. A specific guidance on the conditions under which these methods can be used to identify a na-nomaterial by employing appropriate quantity or metrics conversion should be provided.  The ‘polydispersity‘ and ‘upper size limit‘ Polydispersity is a challenge for the measurement of particle size distribution for the EC NM definition, specifically for materials with high polydispersity index and broad size distribution especially when the volume or mass of the fraction containing particles below 100 nm is very small. Therefore a dedicated guidance should be provided that allows applying an upper size limit in measurements and particle statistics. KW - Nanomaterial KW - EU Definition of nanomaterial KW - Nanoparticles PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-432339 UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D7.10.pdf SP - 1 EP - 68 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-43233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Martınez-Blanco, J. A1 - Peters, M. V. A1 - Hecht, S. A1 - Grill, L. T1 - Observing single-atom diffusion at a molecule-metal interface N2 - The dynamics at the interface between a close-packed porphyrin monolayer and Au(111) is investigated by time-dependent scanning tunneling microscopy, detecting the motion of single-interface adatoms in real space. Imaging sequences reveal predominant switching of the molecular appearance in adjacent molecules, pointing to a spatial correlation that is consistent with adatom diffusion from one molecule to the next. In some cases, the number of switching molecules is drastically increased, indicating collective switching events. In addition to the thermally induced motion of adatoms at the interface, also voltage pulses from the microscope tip can induce the process—revealing different yields in agreement with the model of adatom hopping. KW - STM KW - molecular switch KW - single molecule KW - switching dynamics KW - porphyrin KW - Au(111) PY - 2016 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.035416 U6 - https://doi.org/10.1103/PhysRevB.94.035416 VL - 94 IS - 3 SP - 035416-1 EP - 035416-7 PB - American Physical Society AN - OPUS4-37177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babick, F. A1 - Mielke, Johannes A1 - Wohlleben, W. A1 - Weigel, St. A1 - Hodoroaba, Vasile-Dan T1 - How reliably can a material be classified as a nanomaterial? Available particle-sizing techniques at work N2 - Currently established and projected regulatory frameworks require the classification of materials (whether nano or non-nano) as specified by respective definitions, most of which are based on the size of the constituent particles. This brings up the question if currently available techniques for particle size determination are capable of reliably classifying materials that potentially fall under these definitions. In this study, a wide variety of characterisation techniques, including counting, fractionating, and spectroscopic techniques, has been applied to the same set of materials under harmonised conditions. The selected materials comprised well-defined Quality control materials (spherical, monodisperse) as well as industrial materials of complex shapes and considerable polydispersity. As a result, each technique could be evaluated with respect to the determination of the number-weighted median size. Recommendations on the most appropriate and efficient use of techniques for different types of material are given. KW - Nanomaterial classification KW - Nanoparticle KW - Number-weighted median size KW - Tiered KW - Particle size analysis KW - Nanometrology KW - Characterisation techniques PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-367922 UR - http://link.springer.com/article/10.1007/s11051-016-3461-7 SN - 1388-0764 SN - 1572-896X VL - 18 IS - 6 SP - Article 158, 1 EP - 40 PB - Springer AN - OPUS4-36792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Dohányosová, P. A1 - Lopez, S. A1 - Hodoroaba, Vasile-Dan T1 - Electrospray deposition of nanoparticles on TEM grids N2 - The authors have tested the prototype of an electrospray deposition system developed by the company RAMEM under its trademark IONER. To test the prototype and assess its performance, several materials have been sprayed onto TEM grids and the resulting particle distributions were compared to more traditional sample preparation strategies like the “drop on grid” method. Operation parameters such as the sample flow-rate, capillary – substrate distance, electric field strength and sampling period length have been optimized. It was found that the particles deposited by electrospray generally show a much more homogeneous spatial distribution on the substrate and a substantial increase of the number of single particles, which are much better suited to an automatic image evaluation procedure than the agglomerated particles observed otherwise. The applicability of the technique to a broad range of materials is demonstrated by various examples, but also the influence of the substrate, the choice of the particular TEM grid, on the obtained spatial particle distribution is assessed. KW - Electrspray deposition KW - Electron microscopy KW - Nanoparticles KW - Sample preparation PY - 2016 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/electrospray-deposition-of-nanoparticles-on-tem-grids/459E634B7F74D474A19E15E69DA82E5D U6 - https://doi.org/10.1017/S1431927616010072 SN - 1431-9276 SN - 1435-8115 VL - 22 IS - Suppl 3 SP - 1846 EP - 1847 PB - Cambridge AN - OPUS4-38436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Babick, F. A1 - Uusimäki, T. A1 - Müller, P. A1 - Verleysen, E. A1 - Hodoroaba, Vasile-Dan T1 - Evaluation of electron microscopy techniques for the purpose of classification of nanomaterials N2 - Electron microscopy techniques such as TEM, STEM, SEM or TSEM (transmission in SEM) are capable of assessing the size of individual nanoparticles accurately. Nevertheless, the challenging aspect is sample preparation from powder or liquid form on the substrate, so that a homogeneous distribution of well-separated (deagglomerated) particles is attained. The systematic study in this work shows examples where the extraction of the critical, smallest particle dimension - as the decisive particle parameter for the classification as a NM - is possible by analysing the sample after ist simple, dry preparation. The consequences of additional typical issues like loss of information due to screening of smaller particles by larger ones or the (in)ability to access the constituent particles in aggregates are discussed. KW - Nanomaterial KW - Electron microscopy KW - Particle size distribution KW - Classification PY - 2016 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/evaluation-of-electron-microscopy-techniques-for-the-purpose-of-classification-of-nanomaterials/0B66A25EA7F7A5A3622C02A359C8304F U6 - https://doi.org/10.1017/S1431927616005523 SN - 1431-9276 SN - 1435-8115 VL - 22 IS - Suppl. 3 SP - 936 EP - 937 PB - Cambridge AN - OPUS4-38445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Babick, F. A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Weigel, St. A1 - Wohlleben, W. T1 - Critical review manuscript with real-world performance data for counting, ensemble and separating methods including in-build mathematical conversion to number distributions submitted for publication N2 - The content of the paper is the assessment of the performance of (conventional) measurement techniques (MTs)with respect to the classification of disperse materials according to the EC recommendation for a definition of nanomaterial. This performance essentially refers to the accurate assessment of the number weighted median of (the constituent) particles. All data and conclusions are based on the analytical study conducted as real-world performance testing. It comprised different types of MTs (imaging, counting, fractionating, spectroscopic and integral) as well as different types of materials. Beside reference materials with well-defined size distribution the study also included several commercial powders (variation of particle composition, morphology, coating, size range and polydispersity). In order to ensure comparability of measurement results, the participants were guided to use uniform protocols in sample preparation, conducting measurements, data analysis and in reporting results. Corresponding documents have been made public, in order to support the reviewing process of the paper, respectively to ensure the reproducibility of data by other users under the same conditions. The scientific paper relies on a comprehensive set of revised measurement data reported in uniform templates, completely describes the experimental procedures and discusses the MTs’ performance for selected materials in detail. Even more, the study is summarised and evaluated, which leads to recommendations for the use of MTs within a tiered approach of NM characterisation. In addition, the paper critically examines the factors that may affect the outcome of such a comparison among different MTs. KW - Nanomaterial KW - Measurement techniques KW - EC definition of nanomaterial KW - Nanoparticles PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-389646 UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D3.3.pdf SP - D3.3, 1 EP - 72 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-38964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saywell, A. A1 - Bakker, A. A1 - Mielke, Johannes A1 - Kumagai, T. A1 - Wolf, M. A1 - García-López, V. A1 - Chiang, P.-T. A1 - Tour, J. M. A1 - Grill, L. T1 - Light-Induced Translation of Motorized Molecules on a Surface N2 - Molecular machines are a key component in the vision of molecular nanotechnology and have the potential to transport molecular species and cargo on surfaces. The motion of such machines should be triggered remotely, ultimately allowing a large number of molecules to be propelled by a single source, with light being an attractive stimulus. Here, we report upon the photoinduced translation of molecular machines across a surface by characterizing single molecules before and after illumination. Illumination of molecules containing a motor unit results in an enhancement in the diffusion of the molecules. The effect vanishes if an incompatible photon energy is used or if the motor unit is removed from the molecule, revealing that the enhanced motion is due to the presence of the wavelength-sensitive motor in each molecule. KW - Diffusion KW - Molecular devices KW - Molecular motor KW - Scanning probe microscopy KW - Photoexcitation KW - Photochemistry KW - Molecular machines PY - 2016 UR - http://pubs.acs.org/doi/abs/10.1021/acsnano.6b05650 U6 - https://doi.org/10.1021/acsnano.6b05650 VL - 10 IS - 12 SP - 10945 EP - 10952 PB - ACS Publications AN - OPUS4-39095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Babick, F. A1 - Uusimäki, T. A1 - Müller, P. A1 - Verleysen, E. A1 - Hodoroaba, Vasile-Dan T1 - Evaluation of electron microscopy techniques for the purpose of classification of nanomaterials N2 - One current and much-debated topic in the characterization of nanomaterials (NM) is the implementation of the recently introduced recommendation on a definition of a nanomaterial by the European Commission. All currently available sizing techniques able to address nanoparticles were systematically evaluated. It was demonstrated that particle sizing techniques like: analytical centrifugation, particle tracking analysis, single-particle inductively coupled plasma mass-spectrometry, differential electrical mobility analysis, dynamic light scattering, small angle X-ray scattering, ultrasonic attenuation spectrometry, but also gas Adsorption analysis based on the BET-method can be applied for a screening classification. However, the quality of the results depends on the individual material to be classified. For well-dispersed, nearly spherical (nano)particles most of the sizing techniques can be applied in a quick and reliable way. In contrast, the classification of most real-world materials is a challenging task, mainly due to non-spherical particle shape, large polydispersity or strong agglomeration/ aggregation of the particles. In the present study it was shown that these issues can be resolved in most cases by electron microscopy as a confirmatory classification technique. Electron microscopy techniques such as TEM, STEM, SEM or TSEM transmission in SEM) are capable of assessing the size of individual nanoparticles accurately (see Figures 1 and 2). Nevertheless the challenging aspect is sample preparation from powder or liquid form on the substrate, so that a homogeneous distribution of well-separated (deagglomerated) particles is attained. The systematic study in this work shows examples where the extraction of the critical, smallest particle dimension - as the decisive particle parameter for the classification as a NM - is possible by analysing the sample after its simple, dry preparation. The consequences of additional typical issues like loss of information due to Screening of smaller particles by larger ones or the (in)ability to access the constituent particles in aggregates are discussed. T2 - European Microscopy Congress emc 2016 CY - Lyon, France DA - 28.08.2016 KW - Nanomaterial classification KW - Nanoparticles KW - Electron microscopy PY - 2016 SN - 9783527808465 U6 - https://doi.org/10.1002/9783527808465.EMC2016.5767 SP - 13 EP - 14 PB - Wiley-VCH AN - OPUS4-44087 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Salge, T. A1 - Mielke, Johannes A1 - Ortel, Erik A1 - Schmidt, R. T1 - Characterisation of nanoparticles by means of high-resolution SEM/EDS in transmission mode N2 - Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass – thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS. T2 - European Microbeam Analysis Society’s 14th European Workshop on Modern Developments and Applications in Microbeam Analysis (EMAS 2015) CY - Portorož, Slovenia DA - 03.05.2015 KW - High-resolution KW - SEM KW - T-SEM KW - EDX KW - Nanoparticles PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-355628 UR - http://iopscience.iop.org/article/10.1088/1757-899X/109/1/012006 SN - 1757-899X VL - 109 SP - 012006-1 EP - 012006-12 PB - IOP Publishing Ltd CY - Bristol, UK AN - OPUS4-35562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Babick, F. A1 - Ullmann, C. T1 - Evaluation of particle sizing techniques for the implementation of the EC definition of a nanomaterial N2 - What is a nanomaterial? Beyond a pure academic interest, this question has substantial im-plications for consumer protection and regulatory purposes. The European Commission has recommended a definition of nanomaterial (2011/696/EU), which states that a given material is considered a nanomaterial if more than 50 % of the particles in the number size distribution have a smallest dimension between 1 and 100 nm. Although several well established particle sizing techniques exist, the implementation of this definition for any particulate material remains a metrological challenge. The European research project NanoDefine (http://www.nanodefine.eu) has the aim of pro-viding help for the implementation of the definition. One central task is the performance evaluation of the available particle sizing techniques. For this purpose, a wide variety of real world materials has been selected. All available sizing techniques, including imaging, mobility-based and static scattering techniques, independent whether being counting, fractionating, spectroscopic or integrally sizing, will be applied to all of the projects materials to test the techniques performance and to establish their ranges of applicability. Because most of the techniques do not measure in number metrics as required in the nanomaterial definition, the quality of the conversion to the number based particle size distribution is assessed as well. Special care is taken on suitable sample preparation procedures as one of the most chal-lenging issues towards reaching a highly accurate result. Within this contribution, first results of the performance testing of state of the art characterisation techniques on the unique set of NanoDefine real world materials are going to be presented. From these results, first conclu-sions about the material dependent ranges of applicability for the considered particle sizing techniques can be drawn. The technique specific advantages and shortcomings with respect to the application of the EC definition as well as the analytical challenges encountered will be highlighted. Acknowledgements: The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 604347. T2 - PARTEC CY - Nürnberg, Germany DA - 19.04.2016 KW - Nanomaterial PY - 2016 AN - OPUS4-35802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böckmann, H. A1 - Liu, S. A1 - Mielke, Johannes A1 - Gawinkowski, S. A1 - Walluk, J. A1 - Grill, L. A1 - Wolf, M. A1 - Kumagai, T. T1 - Direct observation of photoinduced tautomerization in single molecules at a metal surface N2 - Molecular switches are of fundamental importance in nature, and light is an important stimulus to selectively drive the switching process. However, the local dynamics of a conformational change in these molecules remain far from being completely understood at the single-molecule level. Here, we report the direct observation of photoinduced tautomerization in single porphycene molecules on a Cu(111) surface by using a combination of low-temperature scanning tunneling microscopy and laser excitation in the near-infrared to ultraviolet regime. It is found that the thermodynamically stable trans configuration of porphycene can be converted to the metastable cis configuration in a unidirectional fashion by photoirradiation. The wavelength dependence of the tautomerization cross section exhibits a steep increase around 2 eV and demonstrates that excitation of the Cu d-band electrons and the resulting hot carriers play a dominant role in the photochemical process. Additionally, a pronounced isotope effect in the cross section (∼100) is observed when the transferred hydrogen atoms are substituted with deuterium, indicating a significant contribution of zero-point energy in the reaction. Combined with the study of inelastic tunneling electron-induced tautomerization with the STM, we propose that tautomerization occurs via excitation of molecular vibrations after photoexcitation. Interestingly, the observed cross section of ∼10–19 cm2 in the visible–ultraviolet region is much higher than that of previously studied molecular switches on a metal surface, for example, azobenzene derivatives (10–23–10–22 cm2). Furthermore, we examined a local environmental impact on the photoinduced tautomerization by varying molecular density on the surface and find substantial changes in the cross section and quenching of the process due to the intermolecular interaction at high density. KW - STM KW - Pophycene PY - 2016 U6 - https://doi.org/10.1021/acs.nanolett.5b04092 SN - 1530-6984 SN - 1530-6992 VL - 16 IS - 2 SP - 1034 EP - 1041 PB - ACS AN - OPUS4-35803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wohlleben, W. A1 - Mielke, Johannes A1 - Bianchin, A. A1 - Ghanem, A. A1 - Freiberger, H. A1 - Rauscher, H. A1 - Gemeinert, Marion A1 - Hodoroaba, Vasile-Dan T1 - Reliable nanomaterial classification of powders using the volume-specific surface area method N2 - The volume-specific surface area (VSSA) of a particulate material is one of two apparently very different metrics recommended by the European Commission for a definition of "nanomaterial" for regulatory purposes: specifically, the VSSA metric may classify nanomaterials and non-nanomaterials differently than the median size in number metrics, depending on the chemical composition, size, polydispersity, shape, porosity, and aggregation of the particles in the powder. Here we evaluate the extent of agreement between classification by electron microscopy (EM) and classification by VSSA on a large set of diverse particulate substances that represent all the anticipated challenges except mixtures of different substances. EM and VSSA are determined in multiple labs to assess also the level of reproducibility. Based on the results obtained on highly characterized benchmark materials from the NanoDefine EU FP7 project, we derive a tiered screening strategy for the purpose of implementing the definition of nanomaterials. We finally apply the Screening strategy to further industrial materials, which were classified correctly and left only borderline cases for EM. On platelet-shaped nanomaterials, VSSA is essential to prevent false-negative classification by EM. On porous materials, approaches involving extended Adsorption isotherms prevent false positive classification by VSSA. We find no false negatives by VSSA, neither in Tier 1 nor in Tier 2, despite real-world industrial polydispersity and diverse composition, shape, and coatings. The VSSA screening strategy is recommended for inclusion in a technical guidance for the implementation of the definition. KW - Nanomaterial KW - Nanomaterial classification KW - Regulation KW - VSSA KW - Size measurement KW - Particle size PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-391450 SN - 1388-0764 SN - 1572-896X VL - 19 IS - 2 SP - Article 61, 1 EP - 16 PB - Springer Nature AN - OPUS4-39145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rauscher, H. A1 - Mech, A. A1 - Gaillard, C. A1 - Stintz, M. A1 - Wohlleben, W. A1 - Weigel, St. A1 - Ghanem, A. A1 - Hodoroaba, Vasile-Dan A1 - Babick, F. A1 - Mielke, Johannes T1 - Recommendations on a revision of the EC definition of nanomaterial based on analytical possibilities; updated N2 - In October 2011 the European Commission (EC) published a "Recommendation on the definition of na-nomaterial" (2011/696/EU), to promote consistency in the interpretation of the term "nanomaterial" for legislative and policy purposes in the EU. The EC NM Definition includes a commitment to its review in the light of experience and of scientific and technological developments. This review is ongoing in 2017 and as a contribution to the review the Joint Research Centre of the European Commission (JRC) has already developed a series of three scientific-technical reports with the title: “Towards a review of the EC Recommendation for a definition of the term nanomaterial” which provides to the EC policy services sci-ence-based options on how the definition could be revised or supported with additional guidance. The overarching nature and wide scope of the EC NM Definition, as it does not exclude a priori any particulate material regardless the state, form and size, creates many analytical challenges in its imple-mentation for all stakeholders, including enterprises and regulators. The NanoDefine project has as core objective to support the implementation of the EC NM Definition. In an earlier report1 key aspects of the EC NM Definition were addressed, with the goal to improve the implementability of the EC NM Definition. Based on further developments and results obtained in NanoDefine project that first report was updated and is presented here. The key aspects are discussed based on the results of four years of research performed within the framework of the project. As a result this report assesses how well the requirements of the EC NM Definition can be fulfilled with currently available analytical possibilities. It presents recommendations and options on a revision of the EC NM Definition to improve the implementability of the definition based on currently available analytical possi-bilities, according to the state of the art in 2017. Of the technical issues considered in this report, the following seem to deserve the most attention in terms of clarification of the definition and/or provision of additional implementation guidance: 'external dimension', ‘number based particle size distribution‘, ‘polydispersity‘ and ‘upper size limit‘, the term ‘particle’, the ‘means to prove that a material is not a nanomaterial‘ and ‘the role of the volume specific sur-face area (VSSA)‘, and "particulate materials'. KW - EU definition of a nanomaterial KW - Nanoparticles KW - Revision KW - Update 2017 PY - 2017 UR - http://www.nanodefine.eu/index.php/nanodefine-publications/nanodefine-technical-reports SP - D7.10, 1 EP - D7.10, 71 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-43540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Dohányosová, P. A1 - Müller, P. A1 - López-Vidal, S. A1 - Hodoroaba, Vasile-Dan T1 - Evaluation of electrospray as a sample preparation tool for electron microscopic investigations: Toward quantitative evaluation of nanoparticles N2 - The potential of electrospray deposition, for the controlled preparation of particles for imaging in electron microscopes, is evaluated on various materials: from mono-modal suspensions of spherical particles to multimodal suspensions and to real-world industrial materials. It is shown that agglomeration is reduced substantially on the sample carrier, compared with conventional sample preparation techniques. For the first time, it is possible to assess the number concentration of a tri-modal polystyrene suspension by electron microscopy, due to the high Deposition efficiency of the electrospray. We discovered that some suspension stabilizing surfactants form artifact particles during electrospraying. These can be avoided by optimizing the sprayed suspension. KW - Electrospary KW - Nanoparticles KW - Sample preparation KW - TEM grid KW - SEM PY - 2017 U6 - https://doi.org/10.1017/S1431927616012587 SN - 1431-9276 SN - 1435-8115 VL - 23 IS - 1 SP - 163 EP - 172 PB - Cambridge University Press AN - OPUS4-39244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Wohlleben, W. A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Zimathies, Annett A1 - Bianchin, A. A1 - Lecloux, A. A1 - Roebben, G. A1 - Rauscher, H. A1 - Gibson, N. T1 - Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial N2 - The VSSA approach has the important advantage over classifying, imaging and counting techniques that it does not involve dispersion protocols. Further, the BET technique as the basis for VSSA determination it is in widespread use, generates low costs and is specified for many commercial materials. Finally, the same equipment allows for a deeper analysis by full isotherm evaluation. The present deliverable assesses all NanoDefine powders, supplemented by further real-world materials (in total 26 powders), and quantitatively compares the relationship between the median size (by Electron Microscopy – considered as benchmark for the EC nanomaterial definition) vs. the size derived from VSSA. The VSSA method mitigates the challenges of EM to assess the thickness of platelets, but worked as well on fibbers and particles of irregular shapes. A screening strategy is proposed. If applied to the further data from real-world materials as validation set, this screening does achieve a correct classification, leaving only borderline materials for tier 2 assessment. KW - Nanomaterial KW - Classification KW - Regulation KW - VSSA KW - Size measurement KW - Particle size PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-398938 SP - 1 EP - 26 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-39893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sarma, Dominik A1 - Mielke, Johannes A1 - Sahre, Mario A1 - Beck, Uwe A1 - Hodoroaba, Vasile-Dan A1 - Rurack, Knut T1 - TSEM-based contour analysis as a tool for the quantification of the profile roughness of silica shells on polystyrene core particles N2 - Core-shell (CS) particles with a polymeric core and a silica shell play an important role in the materials and (bio)analytical sciences. Besides the establishment of reliable synthesis procedures, comprehensive particle characterization is essential for batch-to-batch reproducibility and objective performance assessment across architectures, protocols, and laboratories. Particle characterization with respect to size, size distribution, shell thickness and texture, surface area and roughness or materials composition is commonly conducted with different analytical methods, often on different samples. Our approach uses a dual-mode TSEM/SEM set-up with an EDX detector to obtain a complementary data set with sufficient statistical confidence of one and the same sample on a single instrument. Our protocol reveals information about size, size distribution and shell thickness of the various particles employed from overview images, while an increased field of view (FOV) and high-resolution EDX analysis yields detailed information on shell texture and elemental composition. An image analysis tool was developed to derive and quantify the profile roughness of CS particles from individual beads. Comparison with surface roughness data from AFM showed a similar trend in roughness across the series of particles. Reliable classification into smooth and rough is proposed and roughness changes within different particle batches were tracked systematically. KW - Core-shell particles KW - Electron microscopy KW - Transmission mode KW - Roughness KW - Image analysis PY - 2017 U6 - https://doi.org/10.1016/j.apsusc.2017.07.099 SN - 0169-4332 SN - 1873-5584 VL - 426 IS - 1 SP - 446 EP - 455 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-42256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Dohányosová, P. A1 - Müller, P. A1 - Lopez, S. A1 - Hodoroaba, Vasile-Dan T1 - Electrospray as a sample preparation tool for electron microscopic investigations: Toward quantitative evaluation of nanoparticles N2 - The potential of electrospray deposition, for the controlled preparation of particles for imaging in electron microscopes, is evaluated on various materials: from mono-modal suspensions of spherical particles to multimodal suspensions and to real-world industrial materials. It is shown that agglomeration is reduced substantially on the sample carrier, compared with conventional sample preparation techniques. For the first time, it is possible to assess the number concentration of a tri-modal polystyrene suspension by electron microscopy, due to the high deposition efficiency of the electrospray. We discovered that some suspension stabilizing surfactants form artifact particles during electrospraying. These can be avoided by optimizing the sprayed suspension. KW - Electrospray deposition KW - Nanoparticles KW - SEM KW - TEM KW - Sample preparation PY - 2017 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/electrospray-as-a-sample-preparation-tool-for-electron-microscopic-investigations-toward-quantitative-evaluation-of-nanoparticles/483B212FF290B7EC001A212A19E4E72A U6 - https://doi.org/10.1017/S1431927617010145 SN - 1435-8115 SN - 1431-9276 VL - 23 IS - S1 (July) SP - 1896 EP - 1897 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-42453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Cios, G. A1 - Tokarski, T. A1 - Mansfeld, Ulrich A1 - Ortel, Erik A1 - Mielke, Johannes A1 - Pellegrino, F. A1 - Maurino, V. T1 - Towards 3D Understanding of Non-spherical Nanoparticles by Transmission Kikuchi Diffraction (TKD) for Improved Particle Size Distribution by Electron Microscopy N2 - In this paper one refined approach is applied to determine the exact orientation of bipyramidal TiO2 nanoparticles prepared with good dispersion as almost isolated particles on a carbon TEM grid. The advantages of the recently developed high-throughput Transmission Kikuchi Diffraction (TKD) are used to identify quickly and reliably the geometrical orientation of the crystalline TiO2 nanoparticle bipyramids (anatase) on a statistically relevant number of particles. KW - Nanoparticles KW - Transmission Kikuchi Diffraction (TKD) KW - Electron microscopy KW - TiO2 KW - 3D PY - 2020 U6 - https://doi.org/10.1017/S1431927620013999 VL - 26 IS - S2 SP - 260 EP - 261 PB - Cambridge University Press CY - Cambridge, UK AN - OPUS4-51772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pellegrino, Francesco A1 - Ortel, Erik A1 - Mielke, Johannes A1 - Schmidt, R. A1 - Maurino, V. A1 - Hodoroaba, Vasile-Dan T1 - Customizing New Titanium Dioxide Nanoparticles with Controlled Particle Size and Shape Distribution: A Feasibility Study Toward Reference Materials for Quality Assurance of Nonspherical Nanoparticle Characterization N2 - An overview is given on the synthesis of TiO2 nanoparticles with well-defined nonspherical shapes (platelet like, bipyramidal, and elongated), with the focus on controlled, reproducible synthesis, as a key requirement for the production of reference materials with homogeneous and stable properties. Particularly with regard to the nanoparticle shapes, there is a high need of certified materials, solely one material of this type being commercially available since a few months (elongated TiO2). Further, measurement approaches with electron microscopy as the golden method to tackle the nanoparticle shape are developed to determine accurately the size and shape distribution for such nonspherical particles. A prerequisite for accurate and easy (i.e., automated) image analysis is the sample preparation, which ideally must ensure a deposition of the nanoparticles from liquid suspension onto a substrate such that the particles do not overlap, are solvent-free, and have a high deposition density. Challenges in the Synthesis of perfectly monodispersed and solvent-free TiO2 nanoparticles of platelet and acicular shapes are highlighted as well as successful measurement approaches on how to extract from 2D projection electron micrographs the most accurate spatial information, that is, true 3D size, for example, of the bipyramidal nanoparticles with different geometrical orientations on a substrate. KW - Nanoparticles KW - Titanium dioxide KW - Reference materials KW - Standardisation KW - Particle size and shape distribution PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-538849 VL - 24 IS - 6 SP - 1 EP - 10 PB - Wiley-VCH AN - OPUS4-53884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -