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Item type:Publication, Access status: without files , Shaping the electric field: overcoming geometric inhomogeneities in the electrochemical fabrication of mesoporous materialsIntegrating porous systems such as mesoporous silicon (pSi) into reliable macroscopic devices for sensing, photonics and energy storage requires stringent control over their structural homogeneity. While radial variations in layer thickness and porosity are frequently attributed to edge sealing effects or pinned gas, the macroscopic impact of the electrochemical cell’s internal geometry is largely overlooked. Using pSi as a model system, we demonstrate that the insulating cell body acts as a significant field-shaping component. Combining 2D axisymmetric finite element simulations of the current distribution with spatially resolved near-infrared (NIR) spectrometry, we investigate distortions caused by standard cell features. We reveal that the internal container widening step, commonly used to accommodate counter electrodes, strongly compresses the electric field and generates localized, ring-shaped zones of accelerated etching. Optimizing this step height reduced the radial thickness deviation of a pSi layer 6-fold to just 2%. Furthermore, predictive simulations demonstrate that internal obstacles, such as stirring rods, can be deliberately positioned to either prevent unwanted current shadows or actively manipulate the current distribution for precise three-dimensional structuring. Ultimately, mindful hardware design that prioritizes spatial current distribution is a critical and efficient strategy to maximize the yield of highly homogeneous porous media, directly enhancing their scalability and performance in functional nanomaterial applications.Publicationtype: Journal Article11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Multimodal synchrotron X-ray analysis of palm-leaf manuscripts: structural and compositional signatures of botanical genus, manufacture, and provenance(Springer, 2026-10-06); ; ; ; Palm-leaf manuscripts are cultural artifacts from South and Southeast Asia, yet diverse preparation methods and degradation histories complicate material characterization and comparison. We use a multimodal synchrotron approach combining small- and wide-angle X-ray scattering with X-ray fluorescence to extract structural and compositional descriptors from unprocessed leaves, writing supports, and manuscripts. Supervised learning evaluates differences related to genus, processing stage, and geographical origin. The processing stage is classified reliably, whereas genus separation is clearer in processed materials than in unprocessed leaves. Origin classification shows partial separability, with distinct regional profiles and overlaps reflecting shared preparation traditions, class imbalance, and botanical and degradation-related factors. Classification relies on multivariate combinations of crystallinity, fibril orientation, and elemental descriptors. This scalable, non-destructive framework supports comparison of collections and investigation of material similarities among traditions. The classifications represent comparative material profiles rather than definitive provenance assignments and must be combined with codicological and historical evidence.Publicationtype: Journal Article22 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Melting point depression of Poly(ethylene oxide) crystals under extreme nanoconfinement(American Chemical Society (ACS), 2026-09-08); ; ; Liu, GuomingPolymer crystallization under nanoscale confinement is governed by finite-size and interfacial effects, yet its behavior at length scales approaching the lamellar thickness remains poorly understood. Here, we investigate the crystallization of poly(ethylene oxide) (PEO) with varying molecular weights confined within silicon nanopores (d ∼ 7–8 nm). Crystallization is strongly suppressed, with the crystallization temperature approaching the homogeneous nucleation regime while deviating from conventional volume scaling. Furthermore, the melting temperature exhibits a pronounced reduction (∼20 K), indicating that lamellar thickness is directly constrained by the geometry. Interestingly, a transition from an extended-chain crystal to a folded-chain crystal occurs in PEO with a molecular weight of 2000 g/mol (PEO<inf>2k</inf>), while PEO with a molecular weight of 1000 g/mol (PEO<inf>1k</inf>) maintains an extended-chain crystal, because the contour length of the PEO<inf>2k</inf> chain exceeds d, whereas that of the PEO<inf>1k</inf> is comparable to d. These results demonstrate that, when the confinement dimension approaches the lamellar thickness, geometric confinement dictates nucleation and attainable crystal dimensions, whereas interfacial interactions govern crystal orientation, thereby defining the fundamental limits of polymer crystallization under extreme nanoconfinement.Publicationtype: Journal Article10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Distinct electrification regimes at solid–liquid interfaces revealed by water isotope substitution(American Chemical Society (ACS), 2026-07-28); ; ; ; Solid–liquid contact electrification is widely studied using diverse experimental geometries that are often implicitly assumed to probe equivalent interfacial processes. Here, we directly test this assumption by comparing immersion–emersion, droplet-based contact, and pressure-driven intrusion–extrusion electrification using the same hydrophobic nanoporous silicon monolith and isotopically substituted liquids (H2O and D2O). Despite identical surface chemistry, isotopic substitution produces qualitatively different electrical responses depending on the wetting regime. Immersion–emersion experiments show polarity inversion between H2O and D2O, while droplet measurements reveal distinct charge evolution and periodic opposite-polarity events. In contrast, forced nanopore intrusion preserves polarity but strongly enhances electrical output for D2O. These results demonstrate that wetting of surface nanoroughness during droplet, vs immersion–emersion, vs complete nanopores wetting upon intrusion–extrusion correspond to fundamentally different electrification states. By using isotope substitution as a controlled probe, this work establishes a general framework for disentangling protocol-dependent effects in solid–liquid contact electrification and triboelectric energy conversion.Publicationtype: Journal Article9 14 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Open metal sites govern hydration kinetics and molecular fluctuations in metal–organic frameworks(American Chemical Society (ACS), 2026-07-01); ; ; ; 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 pectroscopy 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 at the nanoscale.Publicationtype: Journal Article47 48 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Decoupling geometry and surface chemistry in 3D-printed ALD-functionalized porous ceramic channels(American Chemical Society (ACS), 2026-06-29); ; ; Minna, FortuneCapillary-driven transport is traditionally attributed to the static pore geometry and wettability. However, the time-dependent surface energy of metal oxides, amplified by the high surface area of porous media, remains a key yet underexplored aspect. This study introduces a novel manufacturing route capable of decoupling macroscopic geometry from surface chemistry by integrating additive manufacturing combined with colloidal assembly (AMCA) and functionalization by atomic layer deposition (ALD). This approach enables the fabrication of highly porous aluminum(III) oxide (Al2O3) and titanium dioxide (TiO2) ceramic channels after thermal burn-out. Within these structures, the structural and chemical properties are tuned and investigated. Spontaneous imbibition experiments at 0, 6, and 24 h after burn-out reveal a transition from a classical Lucas−Washburn rise to a resistance-limited regime dominated by evaporation and viscous drag. Time-resolved contact-angle measurements revealed that both oxides become superhydrophilic after burn-out and undergo subsequent hydrophobic recovery. Despite TiO2 being intrinsically more hydrophilic, Al2O3 channels consistently exhibited faster imbibition rates and a higher liquid rise. This behavior is attributed to the rapid surface relaxation of Al2O3, which reduces contact-line friction and minimizes pinning at high-energy adsorption sites, thereby enhancing fluid uptake. Macroscopic geometrical variations in printed channels did not affect the imbibition height but scaled linearly with imbibed volume, confirming the successful decoupling of geometric and chemical transport factors. The excellent structural reproducibility of the AMCA-ALD method establishes it as a robust manufacturing platform for programmable capillary transport. This approach provides a general pathway to design porous ceramics with independently engineered geometries and surface chemistries for applications in microfluidics, diagnostics, and catalysis.Publicationtype: Journal Article28 50 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , All-water supercapacitor enabled by 1-nm clay channels(Nature Publishing Group UK, 2026-06-05); ; ; 59 89 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Directional dark field for nanoscale full-field transmission X-ray microscopyDark-field X-ray imaging visualizes structural inhomogeneities through small-angle scattering, but existing directional methods are confined to the micrometer scale. While recent advances have extended dark-field capabilities to nanoscale transmission X-ray microscopy, directional scattering retrieval - critical for characterizing anisotropic nanostructures - has remained inaccessible for imaging resolutions in the sub-micrometer scale. Here, we demonstrate the first directional dark-field setup for nanoimaging, achieving orientation mapping of scattering features below the spatial resolution limit. Our method is experimentally simple to implement with existing transmission X-ray microscopy setups. We validate its performance by successfully resolving sub-resolution test structure orientations, cross-correlating orientational changes within hierarchical nanoporous materials, and mapping the directional arrangement of hydroxyapatite nanocrystals 30 - 70 nm within human tooth enamel. By utilizing shadow regions in the optical configuration, we further extend the detectable scattering vector range, demonstrating a pathway toward size-selective dark-field imaging. This advancement enables the quantitative structural characterization of anisotropic nanomaterials, which are critical to biomineralization, advanced materials, and nanotechnology applications.Publicationtype: Journal Article44 45 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Additive manufacturing of hierarchically porous silicon and silica glass(Deutsche Gesellschaft für Materialkunde e.V. (DGM), 2026-03-24); ; ; ; Publicationtype: Conference Presentation102 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Combined effects of salt and microplastics on evaporation and crystallization dynamics in porous media(American Chemical Society (ACS), 2026-03-18); ; ; ; This study investigates the combined effects of salinity and microplastic contamination on the evaporation process and salt crystallization in porous media through complementary column- and pore-scale experiments. Laboratory soil columns were packed with either pure sand or sand mixed with 5% (w/w) poly(vinyl chloride) (PVC) microplastics and subsequently saturated with freshwater or saline (NaCl) solution. Evaporation and crystallization dynamics were monitored by using mass loss measurements, surface optical and thermal imaging, and synchrotron X-ray tomography. Results show that salinity consistently suppressed evaporation by roughly 25–30%, whereas PVC microplastics enhanced it, generating substantial differences in cumulative water loss across treatments. Moreover, thermal imaging revealed distinct surface responses: NaCl samples developed salt crusts that progressively reduced local temperature contrasts and led to more spatially uniform surface conditions, whereas PVC-NaCl samples exhibited lower mean surface temperatures but substantially higher spatial variability, reflected in larger and more persistent temperature anomalies during drying. Pore-scale μCT imaging further confirmed that microplastics altered crystallization patterns by redistributing salt deposition over the upper part of the sand profile and modifying the nucleation behavior. Together, these findings underscore the complex interplay between microplastics and salinity, with implications for soil moisture regulation, surface energy flux, and environmental monitoring strategies.Publicationtype: Journal Article31 58