Open Access

Water under nanoscale confinement exhibits structural and dynamical states distinct from bulk behavior, yet the role of pore chemistry in governing these states remains insufficiently understood. Herein, the hydration kinetics and molecular-scale fluctuations of water confined within a comprehensive series of MOF-74 metal-organic frameworks incorporating Mg, Ni, Co, and mixed-metal compositions were investigated and compared with those observed in mesoporous MCM-41 silica. In situ impedance spectroscopy resolves a pronounced multistep hydration mechanism in MOF-74, initiated by rapid coordinative binding at open metal sites, followed by cluster formation and final capillary condensation. In contrast to MCM-41 silica, where capillary condensation dominates, the presence of coordinatively unsaturated metal centers fundamentally alters adsorption pathways. Mixedmetal MOF-74 exhibits accelerated and temporally broadened hydration, reflecting heterogeneous distributions of adsorption energies. Broadband dielectric spectroscopy reveals a distinct water-specific relaxation process (w-relaxation) attributed to fluctuations of water clusters interacting with metal nodes. Relaxation rates follow Arrhenius behavior with activation energies increasing in the order Mg < Ni < Co and further enhanced in mixed-metal systems. Remarkably, water confined within MOF-74 remains liquid-like down to 133 K without crystallization, whereas crystallization is observed in MCM-41 silica. All activation data of the MOF-74 systems obey a common Meyer−Neldel compensation relation, indicating cooperative molecular dynamics and suggesting a hindered glass-transition−like process of confined water clusters. These findings demonstrate that open metal sites and metal composition enable programmable control over hydration kinetics and collective water dynamics in microporous frameworks. MOF-74 thus provides a tunable model platform for engineering water-driven transport, catalysis, and energy-relevant processes atthe nanoscale.

Die für die Sicherheit von Mensch und Umwelt sowie für die Messtechnik zuständigen deutschen Bundesbehörden – das Umweltbundesamt, die Bundesanstalt für Arbeitsschutz und Arbeitsmedizin (BAuA), das Bundesinstitut für Risikobewertung (BfR), die Bundesanstalt für Materialforschung und -prüfung (BAM) und die Physikalisch-Technische Bundesanstalt (PTB) – begleiten die rasante Innovation von neuartigen Materialien mit einer langfristigen Forschungsstrategie. Die vorgestellte Strategie zeigt die notwendige Sicherheitsforschung auf, die auf der einen Seite Regulierungsbehörden in die Lage versetzt, neuartige Materialien angemessen bewerten zu können, und auf der anderen Seite auch das „Safe and Sustainable by Design“ für Innovatoren unterstützt.

The ACCORDs project (Green Deal inspired correlative imaging-based characterization for safety profiling of 2D materials) is developing an integrated Knowledge Infrastructure to support harmonised characterization workflows for graphene-family materials and other advanced materials. The platform connects imaging data, physico-chemical characterization, biological testing, and risk-related information within a structured and FAIR-compliant environment. The ACCORDs Knowledge Infrastructure brings together datasets, microscopy images, protocols, and analysis workflows, enabling reproducible characterization approaches and facilitating collaboration across disciplines. The system supports the integration of physico-chemical and biological endpoints, links experimental results to materials and protocols, and enables advanced data analysis, AI/ML-supported workflows, and decision support for safety profiling. This online event aims to introduce the ACCORDs project and demonstrate the capabilities of the Knowledge Infrastructure, including the image atlas, protocol integration, multi-modal characterization approaches, and practical use cases involving graphene-family materials, with potential applicability to other advanced materials. The session will combine short expert contributions from project partners with a live demonstration of the ACCORDs Knowledge Infrastructure.

Accurate analysis of microplastics is based on validated methods and the use of standardised protocols. Therefore, reference materials are essential to determine recovery rates and optimise the existing workflows. Reference materials are well characterised, as well as homogenous and stable in at least one property of interest (Emteborg, 2024). They are intended for a defined use and should mimic the reality in terms of selected particle properties and concentrations. Especially for micro- and nanoplastics, aged surfaces and irregular shapes should be covered. The Quality-by-Design approach helps to select the users need and defines a target product profile with mandatory and desired particle properties (Altmann, 2025). After defining the target specifications, the particle production must be controlled and the particles need to be well characterised. An optimisation process helps to guarantee a consistently high-quality product that complies with the chosen specifications, even over repeated batches. Finally, the materials should be tested for their performance in the intended application and validated for homogeneity and stability. We will address different top-down production processes with their limits and challenges, especially when varying polymer type, shape and size ranges. The required concentration may also need to vary between mg and µg depending on the intended use. For example, when considering the Urban Wastewater Treatment Directive and the monitoring of microplastics in the influent and effluent of the wastewater stream as well as sludge, dfferent needs for various plastics and concentrations are required. The effluent will have less microplastics compared to the influent, while the sludge will likely vary in the polymer types present. Thus, polymer types for particle production should focus on thermoplastics such as polyethylene, polypropylene, polystyrene and polyethylene terephthalate, which are relevant in these scenarios.

Proper physicochemical characterization of advanced materials and complex industrial composites remains a significant challenge, particularly for nanomaterials, whose nanoscale dimensions and mostly complex chemistry challenge the analysis. In this work, we employed a correlative analytical approach that integrates atomic force microscopy (AFM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), time-of-flight secondary ion mass spectrometry (ToF- SIMS), Auger electron spectroscopy (AES), and Raman spectroscopy. This combination enables detailed chemical and structural characterization with sub-micrometer spatial resolution. Three commercial graphene-based materials of varying complexity were selected and investigated to test the analytical performance of this approach. Furthermore, one of the commercial graphene oxide samples was chemically functionalized via amination and fluorination. This allowed us to assess how surface modifications influence both the material properties and the limits of the applied analytical techniques.