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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 46 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Interphase-engineering by atomic layer deposition of nacre-inspired alumina composites(Elsevier, 2026-01-03); ; ; ; Nacre, also known as mother of pearl, is a layered brick-and-mortar structure composed of hard mineral platelets and soft organic protein. Found in the inner shells of certain mollusks, this natural architecture has evolved to optimize mechanical properties for the protection of the organism. The unique structured design of nacre and its exceptional mechanical performance have inspired the development of synthetic nacre-like materials. In this work, we introduce a novel approach for fabricating nacre-inspired ceramic composites using atomic layer deposition (ALD) to engineer the interphase, or “mortar”, between aligned alumina platelets. ALD, known for its sub-nanometer thickness control and conformal coating capabilities, enables uniform tuning of the interphase thickness from 30 nm up to 120 nm, offering a significant advantage in tailoring the mechanical properties of ceramic-ceramic composites. Our results reveal a direct correlation between ALD-deposited aluminum oxide thickness and enhanced mechanical performance, with increased modulus and hardness observed as the mortar thickens. Three-point bending tests further show that flexural strength is maximized with thicker ALD coatings . In situ micromechanical testing reveals crack initiation at surface defects in micro-cantilevers, with cracks effectively deflected by the nacre-inspired architecture. This resultsin an average flexural strength of approximately 400 MPa, achieved without additional heat treatment or sintering. The precision of ALD in creating conformal interphases is critical to the improved structural integrity and performance of the composite, demonstrating its potential asa powerful technique for fabricating high-performance, bio-inspired ceramic composites.Publicationtype: Journal Article40 18 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Printing photonic-based thermal barrier coatings onto metal alloy(Nature Publishing Group, 2025-12-01); ; ; ; Reflective coatings based on photonic crystals and photonic glasses are usually produced by traditional colloidal self-assembly techniques characterised by limited control over the deposition surface and lengthy processing times. The emergence of Additive Manufacturing combined with Colloidal Assembly (AMCA) has enabled fast and precise deposition of homogeneous photonic structures, whilst circumventing issues such as the undesired coffee-ring effect. However, the application of this technique was limited to flat substrates. This study investigates the AMCA of ceramic-based colloidal structures onto metallic curved surfaces, relevant to the field of thermal barrier coatings (TBCs). Our results demonstrate the homogeneous ceramic-based photonic glass coatings can be AMCA-printed on different substrates only when a conscious surface charge matching between the colloidal particles and the substrates is made. It also demonstrates the importance of controlling the contact angle of the suspension on the substrates and the printing geometry strategy, differing from traditional direct writing. We further demonstrate the versatility of this method by printing highly porous three-dimensional gadolinium zirconate structures onto curved Inconel substrates. These coatings are engineered for their use as reflective “photonic-based” thermal barrier coatings (rTBCs), capable of suppressing both radiative and conductive heat transport. The resultant AMCA-printed Gd2Zr2O7 rTBCs outperform state-of-the-art TBCs in terms of their reflectance properties and provide a reliable thermal protection to the underlying Inconel alloy, lowering its temperature by about 150 °C in a torch experiment.Publicationtype: Journal Article68 24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Boosting the mechanical strength and photocatalytic activity of 3D-printed titania aerogels by atomic layer deposition and heat treatment(American Chemical Society (ACS), 2025-11-05); ; König, SandraTitania aerogels are highly porous materials optimal for photocatalysis due to their high surface area. Further spatial structuring by 3D printing improves gas diffusion in the aerogel, leading to a higher photocatalytic activity. However, the aerogel’s mechanical properties are reduced in comparison to non-3D printed aerogels. We hereby present an approach based on atomic layer deposition (ALD) of subnanometer-thin TiO2 layers to compensate for that detrimental effect. The ALD-deposited TiO2 consists of amorphous and anatase phase, with the anatase phase likely crystallizing on the aerogel’s crystallites. Nanoindentation measurements confirm that the TiO2 ALD-coatings improve the aerogel’s mechanical properties. Additionally, it enhances the photocatalytic properties of the TiO2 aerogel, which we attribute to the increased interface area and improved interconnection of the nanoparticle network. By further thermal postprocessing, it is possible to fully crystallize the ALD-deposited TiO2, which shows a complementary effect on photocatalytic performance, improving hydrogen evolution rate by more than 1 order of magnitude from 6.35 to 125 μmol g−1 h−1. The combination of 3D structuring of aerogels with ALD coatings demonstrated in this work could be extended in the future to a wide range of materials where the interplay between mechanical and catalytic properties is vital.Publicationtype: Journal Article33 18 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Raster scan imaging in atomic force microscopy: new perspectives and potential of using signal and system theoryRecent advances in high-performance Atomic Force Microscopy (AFM) allow real-time, atomic-scale imaging, but often require expensive equipment. This work revisits the AFM imaging technique and proposes a novel software-based solution for conventional AFMs operated in tapping mode to achieve both high-speed scans and high-resolution images using existing hardware. By treating an AFM scan as a signal modulation process, this method retrieves AFM images directly from signal demodulation. The method captures and analyzes the AFM probe's feedback signal, decomposing it into low- and high-frequency components. The low-frequency signal, representing raster scan motion, undergoes segmentation. The high-frequency signal, containing image information, is demodulated and segmented. These steps generate two sets of signals used to build the final AFM images. Validated on a standard AFM with extensive experiments at scanning speeds up to 240 μm/s, this flexible and easy-to-implementation method unlocks the potential for high-performance, affordable AFM in materials science research.Publicationtype: Conference Paper63 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Achieving high-temperature stable structural color through nanostructuring in polymer-derived ceramics(American Chemical Society (ACS), 2024-04-18); ; ; ; Structural colors offer a myriad of advantages over conventional pigment-based colors, which often rely on toxic chemical substances that are prone to UV degradation. To take advantage of these benefits in demanding environments, there is growing interest in producing structural colors from ceramics. Polymer-derived ceramics (PDCs) emerge as a compelling choice, presenting two distinct advantages: their enhanced shape ability in their polymeric state associated with impressive temperature resistance once converted to ceramics. This study pioneers the fabrication of noniridescent structural colors from silicon oxycarbide (SiOC) PDC, enabled by the nanostructuring of an inverse photonic glass within the PDC material. This design, a functionally graded material with an inverse photonic glass (FGM-PhG) structure, leverages the innate light-absorbing properties of SiOC, yielding a vivid structural color that maintains its saturation even in white surroundings. This study elucidates the process−structure−properties relationship for the obtained structural colors by investigating each layer of the functionally graded material(FGM) in a stepwise coating deposition process. To further emphasize the exceptional processing flexibility of PDCs, the three-step process is later transferred to an additive manufacturing approach. Finally, the FGM-PhG structural colors are demonstrated to have remarkable thermal stability up to 1000 °C for 100 h, possibly making them the most thermally stable ceramic structural colors to date.Publicationtype: Journal Article32 65 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Mullite photonic glasses with exceptional thermal stability for novel reflective thermal barrier coatings(Springer, 2023-08); ; ; ; Thermal barrier coatings are essential materials systems for insulating and protecting substrates exposed to high temperatures. In such systems, the heat transfer has three possible paths: conduction, convection and irradiation. The higher the operating temperature, the more important it is to control or protect against the radiative component, since the radiative heat flux becomes non-negligible. The radiation can be controlled by the use of ceramic-based photonic nanostructures, namely photonic crystals and photonic glasses, creating so-called reflective thermal barrier coatings. In this work, mullite inverse photonic glasses (PhG) have been produced by thermally induced reaction on sol–gel-based silica structures coated with nanometric films of Al2O3 by atomic layer deposition. The conversion to mullite was carried out following a two-stage heat-treatment. The pre-annealing associated with the further mullite formation results in an excellent structural stability of these PhGs up to 1500 °C, being able to retain their high reflectivity in the near infrared range. Therefore, this structure can be considered for next-generation reflective thermal barrier coatings. Graphical abstract: [Figure not available: see fulltext.]Publicationtype: Journal ArticleScopus© Citations 1 69 71 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A green/sustainable organocatalytic pathway for the preparation of esterified supercritical CO2-dried potato starch productsProduction of renewable and modified starch-based products was achievedusing a sustainable catalyst and an environmentally friendly drying process viasupercritical CO2. Potato starch was modified via a sustainable and green ester-ification process with acetic anhydride reagent implementing a novel organo-catalytic pathway at different periods of time (0.5, 3 and 7 h) by applying anesterification reaction at 120°C targeting intermediate degrees of substitution(i.e., 0.2 < DS <1.5) finding potential applications as polymer packaging mate-rials. The final modified samples were divided into two fractions, where the firstfraction was dried under vacuum at 80°C for 24 h and the second fraction wasdried under supercritical CO2at 40°C and 100 bars for 2 h. The final productswere analyzed using an array of characterization techniques such as Fouriertransform infrared (FTIR), Proton nuclear magnetic resonance (1H-NMR), scan-ning electron microscopy (SEM), X-ray diffraction (XRD), N2physisorption,thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), andKarl Fischer. The chemical structure of both fractions was similar as confirmedby the different characterization techniques. Drying under supercritical CO2pre-served some pores in the modified starch materials as opposed to thermal ovendrying, as was confirmed by N2physisorption measurements. The degree of sub-stitution (DS) was determined using three different techniques; titration, highperformance liquid chromatography (HPLC) and solution state proton nuclearmagnetic resonance (1H NMR) spectroscopy and the values were greater than 0.2 and less than 1.5 indicating intermediate degrees of substitution.Publicationtype: Journal Article34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Electroactive performance and cost evaluation of carbon nanotubes and carbon black as conductive fillers in self-healing shape memory polymers and other composites(Elsevier, 2022-09-23); ; ; ; Multiwalled carbon nanotubes (MWCNT) and carbon black (CB) have been widely used as conductive fillers in electroactive polymer composites. MWCNT-based composites generally have lower resistivity and percolation thresholds, while CB-based ones are considerably cheaper. To balance these pros and cons, ternary composites (TCs) (polymer-MWCNT-CB) can be formulated. Here, we prepared electroactive MWCNT-CB TCs capable of self-healing and with shape memory properties, based on polyketones reversibly-crosslinked via Diels-Alder chemistry. Unexpectedly, the cheaper CB-rich formulations had lower resistivities, thus better electroactive self-healing and shape memory responses. Nonetheless, not all electroactive MWCNT-CB TCs have this clear cost-effectiveness. We evaluated the cost-performance of multiple reported MWCNT-CB TCs systems and found different general trends (positive, negative, and synergistic cost-efficiency relationships). Thus, the cost-effectiveness of these fillers (and their combination) greatly depends on each composite system and what it is intended for. This work includes the first systematic report on cost-performance of MWCNT and CB as conductive fillers.Publicationtype: Journal Article40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Electroactive self-healing shape memory polymer composites based on Diels-Alder chemistry(American Chemical Society (ACS), 2021-11-16); ; ; ; Both shape memory and self-healing polymers have received significant attention from the materials science community. The former, for their application as actuators, self-deployable structures, and medical devices; and the latter, for extending the lifetime of polymeric products. Both effects can be stimulated by heat, which makes resistive heating a practical approach to trigger these effects. Here we show a conductive polyketone polymer and carbon nanotube composite with cross-links based on the thermo-reversible furan/maleimide Diels-Alder chemistry. This approach resulted in products with efficient electroactive shape memory effect, shape reprogrammability, and self-healing. They exhibit electroactive shape memory behavior with recovery ratios of about 0.9; requiring less than a minute for shape recovery; electroactive self-healing behavior able to repair microcracks and almost fully recover their mechanical properties; requiring a voltage in the order of tens of volts for both shape memory and self-healing effects. To the best of our knowledge, this is the first report of electroactive self-healing shape memory polymer composites that use covalent reversible Diels-Alder linkages, which yield robust solvent-resistant polymer networks without jeopardizing their reprocessability. These responsive polymers may be ideal for soft robotics and actuators. They are also a step toward sustainable materials by allowing an increased lifetime of use and reprocessability.Publicationtype: Journal Article15