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    Nanoconfined Low-Temperature Supercritical Water for Thermal Energy Storage
    This project, SuperLow, aims to elucidate the fundamental behavior of nanoconfined supercritical water (cSCWs), with a particular focus on investigating whether pseudo-boiling and pseudo-condensation phenomena can manifest under extreme nanoconfinement conditions. Such insights have the potential to unlock novel pathways for thermal energy storage (TES) technologies. Distinctively, SuperLow employs a pioneering approach that leverages highly non-wetting water–nanoporous material pairs during intrusion–extrusion processes, in contrast to the conventional use of wetting pairs in adsorption–desorption studies. Recent work by the principal investigators demonstrated that this methodology can induce an unprecedented reduction in the critical temperature of water by approximately 275 K, achieving supercritical behavior at near 100 °C—far below the bulk critical point. Despite considerable scientific interest, many fundamental properties of nanoconfined water remain poorly understood. In particular, the influence of nanopore size, topology, and surface hydrophobicity on phase behavior, critical temperature and pressure shifts, and the potential existence of the Widom line require systematic exploration. This project addresses these critical knowledge gaps by integrating high-pressure intrusion–extrusion calorimetry with operando structural characterization techniques and atomistic simulations. Confirming or refuting the presence of the Widom line and associated pseudo-phase transitions in cSCWs not only advances fundamental thermodynamics but also establishes a strong technological foundation for developing thermal energy storage materials optimized for low- to medium-temperature applications—an area currently lacking viable solutions. In the longer term, this innovative approach offers a promising route to enhancing energy efficiency by enabling the recovery of up to 468 TWh/year of waste heat dissipated below 100 °C in Europe alone. The use of inexpensive, abundant, and well-characterized nanoporous materials, e.g. silica, underscores the practical viability of this concept. The overarching goal of SuperLow is to stimulate a paradigm shift in supercritical water applications through the strategic lowering of critical temperatures via nanoconfinement. By intruding water in its liquid state under megapascals of pressure—rather than relying on vapor phase condensation at sub-saturation pressures—this work pioneers a novel experimental framework with broad implications for both fundamental science and sustainable energy technologies.
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    EXC 3120 BlueMat - Research Topic A1: Hydrogen-Driven Nanoporous Materials
    We will develop a hydrogen-enabled acoustic metamaterial. The key parameter is the wavelength of sound, which needs to be (1) small (in the order of mm to cm) to enable miniaturization and (2) tunable to enable device switching. The wavelength is determined by the ratio of elastic modulus to mass density. As these parameters are usually strongly correlated, mate- rials with the required properties do not currently exist. A promising approach, demonstrated in preliminary research by the members of the RA A team, is np-Pd, which substantially changes its elastic compliance when alloyed with hydrogen. Thus, a metal/water hybrid nanomaterial achieves switching when hydrogen is relocated between its metal and water phases under the control of an electric potential bias. This new effect implies that one and the same metallic body can be reversibly switched between a hard-matter-like elastic response characteristic of metals and a supercompliant characteristic of soft matter, such as polymers or biological tissue. The key scientific questions are: How can the underlying materials design be shaped in terms of base metal composition and microstructure? How can the open-system elastic response in a nanoscale material with complex microstructural geometry be understood? How can processing routes for components that meet the requirements of Topic A4 be established?
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    EXC 3120 BlueMat - Research Topic C3: Scattering of NIR and Visible Light by Reversible Plasmonic Cluster Formation
    This research topic aims to develop self-regulating and switchable materials based on thermo-reversible assemblies of plasmonic nanoparticles (NPs) within purpose-designed and 3D-nanoprinted porous structures filled with water. Single spherical plasmonic gold particles have their resonance in the visible range, while plasmonic dimers and larger clusters exhibit broad absorption into the NIR. Thus, reversible (dis)assembly can be used to switch NIR transmission. The NPs will be functionalized with programmable oligonucleotide ligands and placed in 3D-nanoprinted capillaries filled with water, where a fraction of the particles will be bound to the pore walls by thermal treatment or surface chemistry. This design will create energy-selective and adaptive materials that can be used as responsive and switchable optical filters in the visible and NIR range with tailored response times, bringing plasmonic switchability into rigid scaffolds. The key scientific questions are: How do the size, shape, and distribution of nanopores influence the reversible assembly of plasmonic particles? How can we design an engineered environment in which the diffusion and assembly of NPs is controlled? How can we improve the switching time and reproducibility of assembly?
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    EXC 3120 BlueMat - Research Topic B1: Tunable Water Condensation and Evaporation
    Evaporative flows at porous surfaces are significantly influenced by the liquid surface exposed to the vapor phase and the vapor pressure of the liquid at the interface, with additional contributions from hydraulic permeability and hydrophilicity within the porous structure. Our goal is to actively control water condensation and evaporation at the vapor-exposed surfaces of structured materials. The key scientific questions are: How can we fabricate 3D structured porous materials systems that – depending on electrical, photonic, or chemical (pH) stimuli – change their evaporative behavior? How can we characterize, understand, and predict water condensation and evaporation (and drying) across scales? How can we achieve tailor-made switching times, imbibition-drying cycles, and minimal energy losses from viscous dissipation?
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    Schriftartefakte verstehen - Material, Interaktion und Transmission in Manuskriptkulturen - 2. Förderperiode
    Writing is one of the most important cultural techniques to have shaped the world’s societies. For most of human history, writing has been handwriting and has been part of diverse and complex manuscript cultures. Written artefacts have been continuously produced up to our own day, though the invention of printing with moveable types marginalised some while at the same time prompted new ones, not least digital media.Over the past three decades, scholarly interest in written artefacts has increased significantly. Enhanced possibilities for the production, storage, circulation, and analysis of images and texts have stimulated historical and systematic inquiry. Material sciences provide methods for asserting the biological and chemical identities of written artefacts. In Asia and Africa manuscripts and inscriptions are increasingly relevant to cultural heritages, and the vast quantities of manuscripts have begun to be catalogued and made accessible.The time has come to develop a truly global framework for the study of all written artefacts from the beginning of writing to the present day and from all regions having produced such artefacts in a way only possible because of Hamburg’s unique combination of expertise. Universität Hamburg has a long history of excellence in manuscript studies. In addition to the Sonderforschungsbereich "Manuscript Cultures in Asia, Africa and Europe", three European Research Council (ERC) grants, two long-term projects (Akademienprogramm), the large-scale project "Safeguarding the Manuscripts from Timbuktu" and a number of smaller research projects are currently conducted.The proposed Cluster of Excellence "Understanding Written Artefacts" includes altogether forty investigators from the humanities representing twenty-three disciplines and ten from biology, chemistry, computer science, mineralogy, neurocognitive psychology, physics and radiology. They will establish a unified, comparative and comprehensive approach for studying how writing has shaped human societies and cultures, and how these in turn have adapted writing to their needs. Finally, they will produce insights immediately relevant for the preservation of objects belonging to the cultural heritage of all humankind.
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    EXC 3120 BlueMat - Research Topic A2: Electrolyte-Driven Nanoporous Materials
    Nanoporous metals, characterized by their high surface-to-volume ratio, have demonstrated promising surface-controlled chemo-mechanical coupling behaviors that can rival or surpass those of bulk functional materials. These behaviors include bidirectional actuation/sensing and switchable elastic compliance. However, there is a trade-off between amplitude and response time. Our goal is to significantly enhance functional performance by designing multiscale hierarchical nanoporous materials that harmonize large amplitude and rapid switching. Nanoscale ligaments at lower hierarchy levels provide high specific surface area for enhanced functional amplitude, while larger pore channels at upper hierarchy levels facilitate efficient mass transport, accelerating response time. Reducing the smallest ligament/pore sizes to single-digit nanometers will create a huge surface area, enabling (1) significant modulation of the elastic modulus and sound velocity in-operando and (2) substantial enhancement of actuation/sensing output signals through reversible electrochemical surface oxidation in an aqueous environment. This provides the basis for sustainable robotic materials for autonomous locomotion and self-reconfiguration. Key scientific questions include: How can we refine and stabilize the microstructure at the lowest hierarchical level while achieving scalable production of these materials in the form of monolithic and mechanically loadable bodies? How can we maximize both the switching kinetics and amplitude of output signals for bidirectional sensing/actuation and switchable mechanical/acoustic properties?
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    EXC 3120 BlueMat - Research Topic D3: Hydrovoltaics
    BlueMat aims to revolutionize hydrovoltaics by developing next-generation hydrovoltaic material technologies. Our goal within D3 is to create high-performance, multiscale, porous materials and innovative hydrovoltaic device architectures to efficiently harness electrical energy from humidity variations, imbibition and drying cycles. We will systematically evaluate their energy conversion performance under varying humidity levels, temperatures, and operating conditions. Our research will focus on reducing imbibition–drying cycle times while enhancing energy output by leveraging humidity variations and low-grade waste heat. This interdisciplinary program aims to advance hydrovoltaics through cutting-edge experimentation, addressing key challenges, and unlocking new opportunities for sustainable energy generation from ambient environmental sources. We will develop highly adapted material architectures to optimize power, addressing issues like minimum friction, salt crystallization upon drying, or evaporation using aqueous electrolytes or water itself. The efforts in D3 aim to improve energy conversion efficiency, durability, and scalability of hydrovoltaic applications, paving the way for widespread deployment in diverse environmental settings. The key scientific questions include: How can we exploit novel hydrovoltaic mechanisms to generate energy from cyclic imbibition and desiccation of electrolyte-infused porous media? How do non-equilibrium fluid dynamics, surface chemistry, open-circuit potential, and other fundamental factors, including the interaction of imbibition and drying influenced by pore characteristics and external stimuli, affect the proposed scheme? How can we optimize the performance of the hydrovoltaic scheme using concepts like hierarchically porous electrodes and adaptive pore wall coatings?
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    EXC 3120 BlueMat - Research Topic B3: Tunable Hydraulic and Capillarity-Driven Water Flow
    In conventional porous media, hydraulic permeability and capillary pressure during imbibition are determined by static geometry, water–solid interaction, and fluid viscosity. RT B3 aims to integrate mechanisms for stimulus-dependent changes in the pore size and solid- liquid interaction, resulting in tunable permeability and hydrophilicity-induced changes of local capillary forces. Combining this strategy with multiscale 3D structuring and local interface modification will enable materials that can locally and reversibly switch imbibition ability and kinetics. Challenges include the fabrication of multiscale 3D structures and precise hydrophilicity change at local levels. This RT focuses on understanding dynamic fluid–solid interactions upon reversible tuning by external stimuli in 3D multiscale porous structures. Key questions include: How can we explore the water–solid interfacial structure and measure the impact of tunable pore size and hydrophilicity on fluid transport? How can we tailor the flow and permeability rates by adjusting multiscale porosity (“Murray vascularization”) and response to stimuli? How can we fabricate structured 3D (nano)porous materials with locally and reversibly tunable permeability and hydrophilicity?
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    EXC 3120 BlueMat - Research Topic C4: Scattering of Visible Light by Control of Water Distribution
    Porous media with periodic or random structures comparable to the wavelength of light can provide spectrally selective scattering. Here, the optical response or color is no longer dictated by the base materials but by the pore shape, orientation, and arrangement, as well as by pore filling. Embedding water into the pore space and controlling its distribution at the nm- and ?m-scale allows for modifying the scattering, thus opening new possibilities to dynamically adjust or switch optical appearance. Previously, water has only been used to slightly shift the spectral response of periodic media upon water infiltration. However, here, we plan to go beyond this state of the art, achieving broadband control of the spectral response and even switching the color on and off. In this respect, we aim to achieve a similar functionality as in the skin of chameleons or cephalopods, but using water in porous media. The key scientific questions are: How can we design and fabricate structures with self-organized multiscale porosity to have defined optical appearance? How can we control water distribution in multiscale porous framework structures to switch this optical appearance? How can we utilize these effects for switchable structural color and opacity, including adaptive functionality?
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