TiO2-SiO2 Self-Standing Materials bearing Hierarchical Porosity: MUB-200(x) Series toward 3D-Efficient VOC Photoabatement Properties.

Three-dimensional photoactive self-standing porous materials have been synthesized through the integration of soft chemistry and colloids (emulsions, lyotrope mesophases, and P25 titania nanoparticles). Final multiscale porous ceramics bear 700-1000 m2 g-1 of micromesoporosity depending on the P25 nanoparticle contents. The applied thermal treatment does not affect the P25 anatase/rutile allotropic phase ratio. Photonic investigations correlated with the foams' morphologies suggest that the larger amount of TiO2 that is introduced, the larger the walls' density and the smaller the mean size of the void macroscopic diameters, with both effects inducing a reduction of the photon transport mean free path (lt) with the P25 content increase. A light penetration depth in the range of 6 mm is reached, thus depicting real 3D photonic scavenger behavior. The 3D photocatalytic properties of the MUB-200(x) series, studied in a dynamic "flow-through" configuration, show that the highest photoactivity (concentration of acetone ablated and concentration of CO2 formed) is obtained with the highest monolith height (volume) while providing an average of 75% mineralization. These experimental results validate the fact that these materials, bearing 3D photoactivity, are paving the path for air purification operating with self-standing porous monolith-type materials, which are much easier to handle than powders. As such, the photocatalytic systems can now be advantageously miniaturized, thereby offering indoor air treatment within vehicles/homes while drastically limiting the associated encumbrance. This volumetric counterintuitive acting mode for light-induced reactions may find other relevant advanced applications for photoinduced water splitting, solar fuel, and dye-sensitized solar cells while both optimizing photon scavenging and opening the path for the miniaturization of the processes where encumbrance or a foot-print penalty would be advantageously circumvented.

Tumor Lung Visualization and Localization through Virtual Reality and Thermal Feedback Interface.

The World Health Organization estimates that there were around 10 million deaths due to cancer in 2020, and lung cancer was the most common type of cancer, with over 2.2 million new cases and 1.8 million deaths. While there have been advances in the diagnosis and prediction of lung cancer, there is still a need for new, intelligent methods or diagnostic tools to help medical professionals detect the disease. Since it is currently unable to detect at an early stage, speedy detection and identification are crucial because they can increase a patient's chances of survival. This article focuses on developing a new tool for diagnosing lung tumors and providing thermal touch feedback using virtual reality visualization and thermal technology. This tool is intended to help identify and locate tumors and measure the size and temperature of the tumor surface. The tool uses data from CT scans to create a virtual reality visualization of the lung tissue and includes a thermal display incorporated into a haptic device. The tool is also tested by touching virtual tumors in a virtual reality application. On the other hand, thermal feedback could be used as a sensory substitute or adjunct for visual or tactile feedback. The experimental results are evaluated with the performance comparison of different algorithms and demonstrate that the proposed thermal model is effective. The results also show that the tool can estimate the characteristics of tumors accurately and that it has the potential to be used in a virtual reality application to "touch" virtual tumors. In other words, the results support the use of the tool for diagnosing lung tumors and providing thermal touch feedback using virtual reality visualization, force, and thermal technology.

Stabilization of all-aqueous droplets by interfacial self-assembly of fatty acids bilayers.

All-aqueous microdroplets produced by liquid-liquid phase separation have emerged as promising models of artificial cells, and offer new approaches for the solvent-free encapsulation of fragile solutes. Yet, the lack of a membrane on such droplets makes them intrinsically unstable against coarsening, and precludes a fine control over chemical localization, as solutes can freely diffuse through the interface. Herein, we report the construction of stable and impermeable water-in-water emulsions via the interfacial self-assembly of mixed sodium oleate/1-decanol bilayers on dextran-rich droplets produced by segregative liquid-liquid phase separation with poly(ethylene glycol). Lipids spontaneously self-assemble as multilamellar structures at the surface of the droplets as revealed by freeze-fracture transmission electron microscopy and small-angle X-ray scattering. We further demonstrate that the lipid-based membrane is impermeable to oligonucleotides and proteins, but also to a low molecular weight dye, so that a strict chemical encapsulation can be achieved by spontaneous partitioning within the droplets before membrane self-assembly. Taken together, our results highlight the ease of production of fatty acid-stabilized all-aqueous emulsions droplets able to encapsulate a range of solutes without the need of oil or organic solvents, paving the way to the construction of robust membrane-bounded, polymer-rich artificial cells.

Design of Binary Nb2O5-SiO2 Self-Standing Monoliths Bearing Hierarchical Porosity and Their Efficient Friedel-Crafts Alkylation/Acylation Catalytic Properties.

Alkylation of aromatic hydrocarbons is among the most industrially important reactions, employing acid catalysts such as AlCl3, H2SO4, HF, or H3PO4. However, these catalysts present severe drawbacks, such as low selectivity and high corrosiveness. Taking advantage of the intrinsic high acid strength and Lewis and Brønsted acidity of niobium oxide, we have designed the first series of Nb2O5-SiO2(HIPE) monolithic catalysts bearing multiscale porosity through the integration of a sol-gel process and the physical chemistry of complex fluids. The MUB-105 series offers efficient solvent-free heterogeneous catalysis toward Friedel-Crafts monoalkylation and -acylation reactions, where 100% conversion has been reached at 140 °C while cycling. Alkylation reactions employing the MUB-105(1) catalyst have a maximum turnover number (TON) of 104 and a turnover frequency (TOF) of 9 h-1, whereas for acylation, MUB-105(1) and MUB-105(2) yield maximum TON and TOF values of 107 and 11 h-1, respectively. Moreover, the catalysts are selective, producing equal amounts of ortho- and para-substituted alkylated products and greater than 90% of the para-substituted acylated product. The highest catalytic efficiencies are obtained for the MUB-105(1) catalyst, bearing the smallest Nb2O5 particle sizes, lowest Nb2O5 content, and the highest amorphous character. The catalysts presented here are in a monolithic self-standing state, offering easy handling, reusability, and separation from the final products.

An Ultra-Thin Near-Perfect Absorber via Block Copolymer Engineered Metasurfaces.

Producing ultrathin light absorber layers is attractive towards the integration of lightweight planar components in electronic, photonic, and sensor devices. In this work, we report the experimental demonstration of a thin gold (Au) metallic metasurface with near-perfect visible absorption (∼95 %). Au nanoresonators possessing heights from 5 - 15 nm with sub-50 nm diameters were engineered by block copolymer (BCP) templating. The Au nanoresonators were fabricated on an alumina (Al2O3) spacer layer and a reflecting Au mirror, in a film-coupled nanoparticle design. The BCP nanopatterning strategy to produce desired heights of Au nanoresonators was tailored to achieve near-perfect absorption at ≈ 600 nm. The experimental insight described in this work is a step forward towards realizing large area flat optics applications derived from subwavelength-thin metasurfaces.

Tailored self-assembled nanocolloidal Huygens scatterers in the visible.

Existing nanocolloidal optical resonators exhibiting strong magnetic resonances often suffer from multi-step low yield synthesis methods as well as a limited tunability, particularly in terms of spectral superposition of electric and magnetic resonances, which is the cornerstone for achieving Huygens scatterers. To overcome these drawbacks, we have synthesized clusters of gold nanoparticles using an emulsion-based formulation approach. This fabrication technique involved emulsification of an aqueous suspension of gold nanoparticles in an oil phase, followed by controlled ripening of the emulsion. The structural control of the as synthesized clusters, of mean radius 120 nm and produced in large numbers, is demonstrated with microscopy and X-ray scattering techniques. Using a polarization-resolved multi-angle light scattering setup, we conduct a comprehensive angular and spectroscopic determination of their optical resonant scattering in the visible wavelength range. We thus report on the clear experimental evidence of strong optical magnetic resonances and directional forward scattering patterns. The clusters behave as strong Huygens sources. Our findings crucially show that the electric and magnetic resonances as well as the scattering patterns can be tuned by adjusting the inner cluster structure, modifying a simple parameter of the fabrication method. This experimental approach allows for the large scale production of nanoresonators with potential uses for Huygens metasurfaces.

Strategy for Enhancing Ultrahigh-Molecular-Weight Block Copolymer Chain Mobility to Access Large Period Sizes (>100 nm).

Assembling ultrahigh-molecular-weight (UHMW) block copolymers (BCPs) in rapid time scales is perceived as a grand challenge in polymer science due to slow kinetics. Through surface engineering and identifying a nonvolatile solvent (propylene glycol methyl ether acetate, PGMEA), we showcase the impressive ability of a series of lamellar poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) BCPs to self-assemble directly after spin-coating. In particular, we show the formation of large-period (≈111 nm) lamellar structures from a neat UHMW PS-b-P2VP BCP. The significant influence of solvent-polymer solubility parameters are explored to enhance the polymer chain mobility. After optimization using solvent vapor annealing, increased feature order of ultralarge-period PS-b-P2VP BCP patterns in 1 h is achieved. Isolated metallic and dielectric features are also demonstrated to exemplify the promise that large BCP periods offer for functional applications. The methods described in this article center on industry-compatible patterning schemes, solvents, and deposition techniques. Thus, our straightforward UHMW BCP strategy potentially paves a viable and practical path forward for large-scale integration in various sectors, e.g., photonic band gaps, polarizers, and membranes that demand ultralarge period sizes.

Multistability at Room Temperature in a Bent-Shaped Spin-Crossover Complex Decorated with Long Alkyl Chains.

An iron(II) pyridyl-benzohydrazonate-based complex decorated with long alkyl chains is reported as a rare spin-crossover compound displaying a wide thermal hysteresis spanning room temperature. On heating, this compound exhibits a spin transition between a LS ground state and an ordered HS-LS phase with symmetry breaking from monoclinic P21/n into orthorhombic P21212 space groups. During cooling, the compound first transits into a magnetically distinguishable HS-LS phase with monoclinic P21 symmetry before returning into the LS phase. Interconversion between the two distinct HS-LS phases is the result of subtle structural changes in the alkyl chains and produces a second minor thermal hysteresis that superposes to the large one. This unprecedented result shows that the combination of a conventional cooperative spin transition and ligand-driven magnetic changes can promote magnetic tristability at room temperature.

Isomeric Column-Forming Esters and Imides with Varying Curvatures of the Aromatic Plane.

Dibenzo[a,j]coronene-tetracarboxylic alkyl esters and imides with either a centrosymmetric bis-peri substitution pattern or a polar bis-ortho substitution pattern form hexagonal columnar mesophases, which in the case of the imides persist at room temperature. The bis-peri isomers are obtained via a two-fold oxidative photocyclization; the bis-ortho isomers are accessed via a glyoxylic Perkin reaction of triphenylene and naphthalene building blocks. Steric congestion between the substituents and the adjacent benzo protrusion in the bis-ortho esters and imides leads to bending of the aromatic plane, which thus avoids twisting. These isomers surprisingly show a more pronounced liquid crystalline behaviour than their non-bent bis-peri homologs, accommodating non-planarity with columnar order by slipped stacking. Whereas both types of ester and the bis-peri imide show an optical behaviour typical for perylene chromophores, the strongly bent bis-ortho imide distinguishes itself notably from them by its absorption spectrum. The electron acceptor strength of the isomeric diimides is found to differ, the hexagonal (peri) diimide having a 0.20 eV lower LUMO energy than the pentagonal (ortho) isomer.

Hexakis [60]Fullerene Adduct-Mediated Covalent Assembly of Ruthenium Nanoparticles and Their Catalytic Properties.

The C66 (COOH)12 hexa-adduct has been successfully used as a building block to construct carboxylate bridged 3D networks with very homogeneous sub-1.8 nm ruthenium nanoparticles. The obtained nanostructures are active in nitrobenzene selective hydrogenation.

From 1,4-Phenylenebis(phenylmaleate) to a Room-Temperature Liquid-Crystalline Benzo[ghi]perylene Diimide.

The photocyclization of tetraethyl 1,4-phenylenebis(phenylmaleate) in the presence of iodine and oxygen predominantly yields tetraethyl [5]helicene-5,6,9,10-tetracarboxylate, together with small amounts of tetraethyl dibenz[a,h]anthracene-5,6,12,13-tetracarboxylate and tetraethyl benzo[ghi]perylene-3,4,11,12-tetracarboxylate. The helicene tetraester is planarized to the benzoperylene tetraester by Scholl reaction with AlCl3 followed by reesterification of the partially hydrolyzed crude product. Subsequent treatment with a branched alkylamine yields a columnar liquid-crystalline benzoperylene diimide whose mesophase is stable at room temperature despite its limited and non-centrosymmetric alkyl periphery. Its absorption spectrum is markedly red-shifted compared to that of a similar benzoperylene triimide.

Columnar Liquid-Crystalline Dibenzopentacenodithiophenes by Photocyclization.

The twofold glyoxylic Perkin reaction of perylene-3,9-diglyoxylic acid with thiophene-diacetic acid followed by oxidative photocylization and reaction with α-branched primary alkylamines yields columnar liquid-crystalline diimides with two sulfur atoms in the condensed arene system. A broad temperature range of the hexagonal columnar mesophase is induced by racemic doubly branched alkyl chains. The HOMO and LUMO energy levels of these thiophene-derived diimides qualify them as electron donors with respect to perylene diimides.

Stabilization of the Columnar Mesophase of Perylenediimide by Racemic Triple Tails.

Whereas perylene tetracarboxdiimides derived from amino-n-alkanes if at all only show monotropic (thermodynamically unstable) mesogenic self-assembly, the hexagonal columnar liquid crystalline state can be stabilized over a broad temperature range with doubly branched, doubly racemic alkyl residues. An improved tendency to homeotropic surface orientation is observed, and the orientation of the liquid crystalline domains is maintained upon cycling through the crystalline state at room temperature.

Triggering the Mechanical Release of Mineralized Pickering Emulsion-Based Capsules.

Taking advantage of the benefit of Pickering-based emulsions and sol-gel chemistry, we synthesized mineralized Pickering emulsion-based capsules constituted of a dodecane core and a siliceous shell. To trigger the oily core mechanical release, we first made use of the one-step polycondensation synthesis path, reaching limited shell thickness from 43 to 115 nm with a resistance against the application of an external pressure from 0.5 to 6 MPa. When addressing a sequential mineralization route, we were able to reach both better shell homogeneity and higher values of shell thickness from 85 to 135 nm associated with a shell breaking pressure varying from 1.2 to 10 MPa. In this last configuration, the shell homogeneity and thickness are acting cooperatively toward enhancing the shell mechanical toughness and the associated effective breaking pressure of the dodecane@SiO2 core-shell particles.

Hevea brasiliensis prohevein possesses a conserved C-terminal domain with amyloid-like properties in vitro.

Prohevein is a wound-induced protein and a main allergen from latex of Hevea brasiliensis (rubber tree). This 187 amino-acid protein is cleaved in two fragments: a N-terminal 43 amino-acids called hevein, a lectin bearing a chitin-binding motif with antifungal properties and a C-terminal domain (C-ter) far less characterized. We provide here new insights on the characteristics of prohevein, hevein and C-terminal domain. Using complementary biochemical (ThT/CR/chitin binding, agglutination) and structural (modeling, ATR-FTIR, TEM, WAXS) approaches, we show that this domain clearly displays all the characteristics of an amyloid-like proteins in vitro, that could confer agglutination activity in synergy with its chitin-binding activity. Additionally, this C-ter domain is highly conserved and present in numerous plant prohevein-like proteins or pathogenesis-related (PR and WIN) proteins. This could be the hallmark of the eventual presence of proteins with amyloid properties in plants, that could potentially play a role in defense through aggregation properties.

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores.

New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)- or cholesteryl-containing tailor-made dendritic mesomorphic triphenylphosphine oxide ligands on luminescent (M6 Cl(i) 8 )(4+) octahedral cluster cores (M=Mo, W). The LC properties were studied by a combination of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray powder diffraction analyses. While the organic ligands showed various mesophase types ranging from nematic, SmA columnar (SmACol ), SmA, and SmC phases, it turned out that the corresponding clustomesogens formed layered phases (SmA) over a wide range of temperatures that depend on the nature and density of mesogenic groups employed. Intrinsic luminescence properties of the cluster precursors are preserved over the entire range of LC phase existence.

Plank-shaped column-forming mesogens with substituents on one side only.

Prolonged glyoxylation of pyrenyl-1-glyoxylic acid ethyl ester leads to a mixture of isomers with polar pyrenylene-1,8-diglyoxylic acid as the main product, whereas the centrosymmetric 1,6-isomer is obtained in good yield from the corresponding dibromopyrene. Perkin condensations followed by Pd-catalyzed cyclizations lead to isomeric dinaphthopyrene-tetracarboxdiimides that self-assemble into columnar liquid crystals of hexagonal and rectangular symmetry, of which the rectangular mesophases have unusually elongated unit cells. The cisoid diimides with both alkylimide substituents on the same side of the oblong arene system show a much greater tendency to self-assemble into fluid stacks of disks than their centrosymmetric isomers. With racemically branched alkyl substituents, uniform vertical surface alignment of the columns in the high-temperature hexagonal mesophase is resilient to cycling through the lower-temperature rectangular and crystalline phases.

Columnar liquid-crystalline dinaphthoperylenetetracarboxdiimides.

Although the double Friedel-Crafts acylation of arenes with ethyl chloroglyoxylate is hindered by the strongly deactivating effect of the first-entering glyoxylic substituent, the double reaction is successful with the reactive arene perylene under long reaction times and with concomitant ester hydrolysis. The reaction is regiospecific, giving the 3,9-regioisomer exclusively. This perylenylenediglyoxylic acid is condensed first with o-bromophenylacetic acid and then with α-branched alkylamines to yield the title compounds. Whilst the corresponding tetraalkyl esters only show monotropic mesophases, these diimides show enantiotropic columnar mesophases that can be maintained at room temperature if racemically branched alkyl chains of moderate size are used. A palladium-induced C-C bond migration during the build-up of the arene system leads to an isomeric side product of reduced symmetry that can be isolated by aggregation-controlled chromatographic separation. The HOMO and LUMO energies of the title compounds are considerably higher than those of established perylenetetracarboxdiimides.

Regiospecific synthesis of tetrasubstituted phthalocyanines and their liquid crystalline order.

Metal-free and metal(II) all-endo-tetraalkoxy-phthalocyanines of C4h symmetry are synthesised regiospecifically from 3-(2-butyloctyloxy)phthalonitrile with lithium octanolate and subsequent metal ion exchange. The voluminous, yet not overly large, and racemically disordered alkoxy substituent not only renders the cyclotetramerisation regiospecific, but also leads to liquid crystalline self-assembly with attainable clearing temperatures and persisting columnar organisation at room temperature. A rare hexagonal mesophase with twelve columns per hexagonal unit cell is found in the metal-free homologue, whereas the metal complexes show rectangular mesophases. The clearing temperature increases with increasing axial component of the metal ion coordination sphere. At low temperature, significant antiferromagnetic exchange between magnetic centres is observed for the Co(II) homologue, whereas the magnetic centres are magnetically independent in the Cu(II) derivative, in line with the observed higher clearing temperature in the Co(II) case that testifies of stronger interdisk interactions.

Rubber elongation factor (REF), a major allergen component in Hevea brasiliensis latex has amyloid properties.

REF (Hevb1) and SRPP (Hevb3) are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of ß-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.