Tanja Eder

Optical encryption using nanostructured materials provides a powerful route for secure data encoding. In this work, an electrically reconfigurable colloidal photonic platform based on covalent organic framework (COF) particles is described, enabling dynamic and bistable data encryption. Spatially controlled electrophoretic assembly of monodisperse COF particles within patterned cells produces Bragg reflections that are visible only under bright-field (BF) microscopy as strong broadband scattering from nanoscale particle surface roughness conceals the encoded states from the naked eye. By tuning the synthesis time, the particle surface roughness and, thus, the degree of concealment can be precisely controlled. Unlike conventional optical systems, where scattering degrades visibility, we report it as an intrinsic security feature, transforming a loss mechanism into a tool for optical masking. The demonstrated platform combines electrical addressability, conditional optical visibility, and algorithmic decoding to deliver a compact, multifactor encryption system. These results demonstrate colloidal COF dispersions as a versatile class of photonic materials for secure displays, anticounterfeiting, and adaptive optical communication technologies.

3D-printed and densely sintered α-alumina supports with high flexural strength were functionalized with ZIF-8 and MOF-808. The latter was used to catalyze the rapid degradation of nerve-agent simulant dimethyl-4-nitrophenyl phosphate.

Metal-organic frameworks (MOFs) show promising results in various fields, such as gas separation and catalysis, but they face limitations due to problems associated with their low processability. This study addresses these challenges by utilizing postsynthetic modification (PSM) of NH₂-UiO-66 and NH₂-MOF-808 with 1,3,5-benzene tricarbaldehyde (BTCA) to form hybrid aerogels consisting of MOF-loaded covalent organic framework (COF). BTCA-modified MOF nanoparticles via imine bond formation were confirmed by ¹H NMR, FTIR, and solid-state ¹³C NMR spectroscopies. MOF/COF composites were analyzed via TGA, PXRD, BET, and solid-state ¹³C NMR, showing retained crystallinity and increased porosity in comparison to the sum of the individual components. Moreover, improved aerogel mechanical properties and increased MOF loading of up to 75 wt % were achieved for covalently bound aerogels. Hybrid aerogel composites were successfully utilized as catalytic filters for the decomposition of nerve agent simulant and pesticide dimethyl-4-nitrophenylphosphate (DMNP), avoiding secondary pollution associated with MOF powder catalysis.

Ice accretion causes significant energy losses and safety risks across various sectors. Recent research shows that liquid‐like surfaces (LLS) with ice‐shedding properties can be created by covalently attaching linear polymer chains onto smooth substrates with sufficient hydroxyl group densities. To expand the substrate scope for LLS, a novel system using non‐halogenated organosilanes attached to a commercial epoxy‐silicon (EpSi) coating is proposed. The EpSi layer, easily applied using simple methods, serves as a smooth intermediate layer (R_a = 0.94 nm and R_q = 0.76 nm). Air plasma activation increases hydroxyl density on EpSi, enabling LLS formation via simple immersion in an organosilane solution. The resulting coating exhibits low contact angle hysteresis (τ_ice < 20 kPa). Effective LLS is generated regardless of substrate type, coating thickness, or application method. The coating retains its slippery properties after exposure to harsh conditions, including icing/deicing cycles, organic solvents, and acidic environment. It is also highly transparent (T_ave = 84.5%, t = 500 µm) with self‐cleaning and anti‐staining capabilities. This methodology broadens the substrate scope of LLS, offering a sustainable solution to ice accretion challenges.

Liquid-like surfaces featuring slippery, omniphobic, covalently attached liquids (SOCALs) reduce unwanted adhesion by providing a molecularly smooth and slippery surface arising from the high mobility of the liquid chains. Such SOCALs are commonly prepared on hard substrates, such as glass, wafers, or metal oxides, despite the importance of nonpolar elastomeric substrates, such as polydimethylsiloxane (PDMS) in anti-fouling or nonstick applications. Compared to polar elastomers, hydrophobic PDMS elastomer activation and covalent functionalization are significantly more challenging, as PDMS tends to display fast hydrophobic recovery upon activation as well as superficial cracking. Through the extraction of excess PDMS oligomers and fine-tuning of plasma activation parameters, homogeneously functionalized PDMS with fluorinated polysiloxane brushes could be obtained while at the same time reducing crack formation. Polymer brush mobility was increased through the addition of a smaller molecular silane linker to exhibit enhanced dewetting properties and reduced substrate swelling compared to functionalizations featuring hydrocarbon functionalities. Linear polymer brushes were verified by thermogravimetric analysis. The optical properties of PDMS remained unaffected by the activation in high-frequency plasma but were impacted by low-frequency plasma. Drastic decreases in solid adhesion of not just complex contaminants but even ice could be shown in horizontal push tests, demonstrating the potential of SOCAL-functionalized PDMS surfaces for improved nonstick applications.