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Self‐assembling peptides (SAPs) are versatile building blocks in the creation of hierarchical nanostructures. Although SAPs promise precise control over assembled morphology and dimensions, experimental validation is still crucial. In this sense, recent efforts have focused on nanospiral structures, which mimic natural architectures and hold potential for biomedical and nanotechnological applications. Here, it is demonstrated that SARS‐CoV‐2 fusion peptides are able to form specific spiral‐like structures using interfacial assembly as a fabrication methodology, along with fine‐tuning of the spiral ensembles through an imposed interfacial flow due to the uniaxial compression in a Langmuir–Blodgett trough. Molecular characterization by atomic force microscopy, neutron reflectometry, interfacial shear rheology, and infrared spectroscopy, highlighted how variations in fusion peptide sequences influence assembly, highlighting the importance of molecular design. These spiral structures are subsequently modified to serve as templates for metallic replicas, expanding the potential of peptide‐guided self‐assembly in fabricating tailored nanostructured surfaces with sub‐10 nm dimensions over cm2 areas. [ABSTRACT FROM AUTHOR]

Strain sensors for wearable electronic devices have received attention due to their potential application in medicine for physiological monitoring or as part of advanced prosthetics. However, low sensitivity values as well as complex fabrication procedures remain significant challenges limiting the applicability. This work presents the fabrication of a strain sensor based on the separation of silver microplates immobilized on a stretchable substrate. The deposition of the microplates is achieved through the exposition of a glucosamine‐functionalized surface to the Tollens' reagent, being a versatile fabrication methodology able to be implemented in a wide range of substrates. The obtained sensors present a high stretchability (>100%), high conductivity (105 S m–1), good linearity (R2 > 0.98 under 30% strain), good hysteresis properties, and high sensitivity (up to GF = 900 000). Hence, the sensors allow the measurement of very small deformations even in dynamic range, where it presents a stable linear response for the quantification of cyclic deformations of 0.02% strain. Moreover, the applicability of these sensors has been studied in motion‐sensing devices and in a pressure sensor revealing that this technology may expand the potential applications of wearable electronic devices. [ABSTRACT FROM AUTHOR]

The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than a decade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-free compounds, having comparable or even better performance has not yet been reached. In this road, the lead-free ceramics Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT), possessing excellent dielectric, ferroelectric, and piezoelectric properties are regarded as serious candidates for the PZT replacement. Besides, nanostructuring BCZT is of paramount importance to enhance these functionalities even more. Here, BCZT multipodes are designed by template-growth hydrothermal synthesis using hydrogen zirconate titanate nanowires. We demonstrate that the fabricated BCZT multipodes exhibit high dielectric permittivity of 5300 with a temperature stability coefficient of ±5.9% between 20 and 140 °C. A significant recovered energy density of 315.0 mJ/cm3 with high thermal stability and high energy storage efficiency of 87.4%, and enhanced large-signal piezoelectric coefficient d33∗ (310 pm/V) are found. Compared to the traditional BCZT ceramics reported in the literature, relying on high-temperature processing, our sample exhibits boosted energy storage parameters at a much lower temperature. These outcomes may offer a new strategy to tailor eco-responsible relaxor ferroelectrics toward superior energy storage performance for ceramic capacitor applications.

Abstract Strain sensors for wearable electronic devices have received attention due to their potential application in medicine for physiological monitoring or as part of advanced prosthetics. However, low sensitivity values as well as complex fabrication procedures remain significant challenges limiting the applicability. This work presents the fabrication of a strain sensor based on the separation of silver microplates immobilized on a stretchable substrate. The deposition of the microplates is achieved through the exposition of a glucosamine‐functionalized surface to the Tollens’ reagent, being a versatile fabrication methodology able to be implemented in a wide range of substrates. The obtained sensors present a high stretchability (>100%), high conductivity (105 S m–1), good linearity (R2 > 0.98 under 30% strain), good hysteresis properties, and high sensitivity (up to GF = 900 000). Hence, the sensors allow the measurement of very small deformations even in dynamic range, where it presents a stable linear response for the quantification of cyclic deformations of 0.02% strain. Moreover, the applicability of these sensors has been studied in motion‐sensing devices and in a pressure sensor revealing that this technology may expand the potential applications of wearable electronic devices.

Metal-Organic Frameworks (MOFs) attract attention for their intrinsic porosity, large surface area, and functional versatility. To fully utilize their potential in applications requiring precise control at smaller scales, it is essential to overcome challenges associated with their bulk form. This is particularly difficult for 3D MOFs with spin crossover (SCO) behavior, which undergo a reversible transition between high-spin and low-spin states in response to external stimuli. Maintaining their structural integrity and SCO properties at the nanoscale remains a significant challenge, yet these properties make them ideal candidates for sensors, data storage, and molecular switch applications. This study reports the synthesis of nanocrystals of the well-known SCO MOF [Fe 2 (H 0.67 bdt) 3 ]·xH 2 O (1, x = 0-10, bdt 2- = 1,4-benzeneditetrazolate), which exhibits both magnetic and charge transport properties. The nanocrystals are obtained through sonication of macrocrystals, and the preservation of their crystalline structure at the nanoscale is explored using Microcrystal Electron Diffraction (MicroED). A comparison between macro- and nanocrystals highlights the structural integrity and the preservation of charge-transport properties, underlining the potential for further miniaturization of MOFs for advanced technological applications., (© 2024 Wiley‐VCH GmbH.)

Iridium Oxide (IrO2) is a metal oxide with a rutile crystalline structure, analogous to the TiO2 rutile polymorph. Unlike other oxides of transition metals, IrO2 shows a metallic type conductivity and displays a low surface work function. IrO2 is also characterized by a high chemical stability. These highly desirable properties make IrO2 a rightful candidate for specific applications. Furthermore, IrO2 can be synthesized in the form of a wide variety of nanostructures ranging from nanopowder, nanosheets, nanotubes, nanorods, nanowires, and nanoporous thin films. IrO2 nanostructuration, which allows its attractive intrinsic properties to be enhanced, can therefore be exploited according to the pursued application. Indeed, IrO2 nanostructures have shown utility in fields that span from electrocatalysis, electrochromic devices, sensors, fuel cell and supercapacitors. After a brief description of the IrO2 structure and properties, the present review will describe the main employed synthetic methodologies that are followed to prepare selectively the various types of nanostructures, highlighting in each case the advantages brought by the nanostructuration illustrating their performances and applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The thermal behavior of DBN and DBU PILs with carboxylic acids of varying chain length was explored. • The effects of base, acid, and temperature on C p , m 0 of the PILs were studied. • The T g and C p , m 0 of the PILs show a significant dependence with the base. • PILs can display high values of excess heat capacities, depending on their ionicity. • Evidence for the occurrence of nanostructuration in PILs with acids of longer chain length. Herein, we report the thermal behavior and high-precision heat capacity values, at T = 298.15 K, and in the range from 283 to 363 K, for several protic ionic liquids (PILs), derived from the 1:1 liquid mixtures of the organic superbases 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with some carboxylic acids (propionic, butyric, hexanoic and octanoic). Glass transition, T g , crystallization, T c , cold-crystallization, T cc , and melting, T m , temperatures were determined for the PILs studied, showing marked differences with the base – T g is lower for all DBN PILs, and no T m , T c , and T cc could be obtained for the DBU PILs. The standard molar heat capacities, C p , m 0 , were obtained with an uncertainty of less than ±0.3 % and their dependence on the base and on the acid's chain length was studied in detail. The C p , m 0 of the DBU PILs were found to be significantly higher than those of the corresponding DBN PILs, which corroborates the greater ionic character of DBU PILs. The heat capacity data suggested the existence of a trend-shift with the chain length of the carboxylic acid. Similar to aprotic ionic liquids, the shift occurs around n = 5 (pentanoic acid) and suggests the existence of some degree of nanostructuration into polar and non-polar domains in PILs with larger acids. Moreover, PILs can display abnormally high excess heat capacities, resulting from the formation of an ionic mixture from neutral species. Analysis of the calculated excess heat capacities indicates that PILs tend to become less ionic as the temperature increases, which goes in accordance with the acid-base equilibrium shift. [ABSTRACT FROM AUTHOR]

Nanocelluloses occur under various crystalline forms that are currently being selectively used for a wide variety of high performance materials. In the present study, two cellulose nanofibers (CF-I) were mercerized by alkaline treatment (CF-II) without degradation, the same molar mass of 560,000 g/mol was measured. Both samples were acid hydrolyzed, leading to cellulose nanocrystals in native (CNC-I) and mercerized (CNC-II) forms. This study focuses on the detailed characterization of these two nanoparticle morphologies (light and neutron scattering, TEM, AFM), surface chemistry (zetametry and surface charge), crystallinity (XRD, 13C NMR), and average molar mass coupled to chromatographic techniques (SEC–MALLS-RI, A4F-MALLS-RI), revealing variations in the packing of the crystalline domains. The crystal size of CNC-II is reduced by half compared to CNC-I, with molar masses of individual chains of 41,000 g/mol and 22,000 g/mol for CNC-I and CNC-II, respectively, whereas the same surface charge density is measured. This study gives an example of complementary characterization techniques as well as results to help decipher the mechanism involved in mercerization. [ABSTRACT FROM AUTHOR]

The terbium(III) ion is a particularly suitable candidate for the creation of surface-based magnetic and luminescent devices. In the present work, we report the epitaxial growth of needle-like objects composed of [Tb(hfac)3·2H2O]n (where hfac = hexafluoroacetylacetonate) polymeric units on muscovite mica, which is observed by atomic force microscopy. The needle-like shape mimics the structure observed in the crystalline bulk material. The growth of this molecular organization is assisted by water adsorption on the freshly air-cleaved muscovite mica. This deposition technique allows for the observation of a significant amount of nanochains grown along three preferential directions 60° apart from another. The magnetic properties and the luminescence of the nanochains can be detected without the need of surface-dedicated instrumentation. The intermediate value of the observed luminescence lifetime of the deposits (132 µs) compared to that of the bulk (375 µs) and the CHCl3 solution (13 µs) further reinforces the idea of water-induced growth.

Iridium Oxide (IrO2) is a metal oxide with a rutile crystalline structure, analogous to the TiO2 rutile polymorph. Unlike other oxides of transition metals, IrO2 shows a metallic type conductivity and displays a low surface work function. IrO2 is also characterized by a high chemical stability. These highly desirable properties make IrO2 a rightful candidate for specific applications. Furthermore, IrO2 can be synthesized in the form of a wide variety of nanostructures ranging from nanopowder, nanosheets, nanotubes, nanorods, nanowires, and nanoporous thin films. IrO2 nanostructuration, which allows its attractive intrinsic properties to be enhanced, can therefore be exploited according to the pursued application. Indeed, IrO2 nanostructures have shown utility in fields that span from electrocatalysis, electrochromic devices, sensors, fuel cell and supercapacitors. After a brief description of the IrO2 structure and properties, the present review will describe the main employed synthetic methodologies that are followed to prepare selectively the various types of nanostructures, highlighting in each case the advantages brought by the nanostructuration illustrating their performances and applications.

The development of advanced piezoelectric α‐quartz microelectromechanical system (MEMS) for sensing and precise frequency control applications requires the nanostructuration and on‐chip integration of this material on silicon material. However, the current quartz manufacturing methods are based on bonding bulk micromachined crystals on silicon, which limits the size, the performance, the integration cost, and the scalability of quartz microdevices. Here, chemical solution deposition, soft‐nanoimprint lithography, and top‐down microfabrication processes are combined to develop the first nanostructured epitaxial (100)α‐quartz/(100)Si piezoelectric cantilevers. The coherent Si/quartz interface and film thinness combined with a controlled nanostructuration on silicon–insulator–silicon technology substrates provide high force and mass sensitivity while preserving the mechanical quality factor of the microelectromechanical systems. This work proves that biocompatible nanostructured epitaxial piezoelectric α‐quartz‐based MEMS on silicon can be engineered at low cost by combining soft‐chemistry and top‐down lithographic techniques. [ABSTRACT FROM AUTHOR]

This article presents a study on Metal-Assisted Chemical Etching (MACE) of silicon in HF-H2O2 using silver nanoparticles as catalysts. Our aim is a better understanding of the process to elaborate new 3D submicrometric surface structures useful for light management. We investigated MACE over the whole range of silicon doping, i.e., p++, p+, p, p−, n, n+, and n++. We discovered that, instead of the well-defined and straight mesopores obtained in p and n-type silicon, in p++ and n++ silicon MACE leads to the formation of cone-shaped macropores filled with porous silicon. We account for the transition between these two pore-formation regimes (straight and cone-shaped pores) by modeling (at equilibrium and under polarization) the Ag/Si/electrolyte (HF) system. The model simulates the system as two nanodiodes in series. We show that delocalized MACE is explained by a large tunnel current contribution for the p-Si/Ag and n-Si/HF diodes under reverse polarization, which increases with the doping level and when the size of the nanocontacts (Ag, HF) decreases. By analogy with the results obtained on heavily doped silicon, we finally present a method to form size-controlled cone-shaped macropores in p silicon with silver nanoparticles. This shape, instead of the usual straight mesopores, is obtained by applying an external anodic polarization during MACE. Two methods are shown to be effective for the control of the macropore cone angle: one by adjusting the potential applied during MACE, the other by changing the H2O2 concentration. Under appropriate etching conditions, the obtained macropores exhibit optical properties (reflectivity ~3 %) similar to that of black silicon.

In this work, we model thin films of β-Ca(BH4)2 to understand how nanostructuration of the material can be an effective way to decrease the dehydrogenation enthalpy. Two different crystallographic faces of Ca(BH4)2 have been investigated (i.e., (001) and (101)), and two reaction pathways have been considered that release hydrogen through the formation of CaH2 and CaB6, respectively. Quantum mechanical calculations predict that size reduction from bulk to nanoscale leads to a sizeable decrease of the decomposition enthalpy of the borohydride of about 5 kJ/molH2. Therefore, the present results corroborate the evidence that nanostructured metal borohydrides show advantages for energy storage applications compared to their bulk counterparts. [ABSTRACT FROM AUTHOR]

This article reports a study to identify optimal synthesis parameters for a pure boron precursor prepared following a patented process developed at CNR-SPIN laboratories, performed in the framework of a collaboration between CNR-SPIN and CERN. Boron is a precursor that plays a crucial role in the MgB2 wire manufacturing, as a consequence, the synthesis parameters of the superconducting phase have been investigated. In this article, we report results for MgB2 samples synthesized at 870 °C for 17nbsp;h under Ar/5% H2 flow and 760 °C for 0.2 h. Magnesiothermic amorphous nanoboron (MANB) and commercial boron nanopowders (purchased from Pavezyum) have been compared in terms of morphological features. MgB2 derived from both sources has been characterized and the superconductive properties in the wire form have been compared. Results demonstrate that the MANB performance is comparable with the nanoboron obtained via gas synthesis. [ABSTRACT FROM AUTHOR]

Abstract Graded structures and nanocellular polymers are two examples of advanced cellular morphologies. In this work, a methodology to obtain low‐density graded nanocellular polymers based on poly(methyl methacrylate) (PMMA)/thermoplastic polyurethane (TPU) blends produced by gas dissolution foaming is reported. A systematic study of the effect of the processing condition is presented. Results show that the melt‐blending results in a solid nanostructured material formed by nanometric TPU domains. The PMMA/TPU foamed samples show a gradient cellular structure, with a homogeneous nanocellular core. In the core, the TPU domains act as nucleating sites, enhancing nucleation compared to pure PMMA and allowing the change from a microcellular to a nanocellular structure. Nonetheless, the outer region shows a gradient of cell sizes from nano‐ to micron‐sized cells. This gradient structure is attributed to a non‐constant pressure profile in the samples due to gas desorption before foaming. The nucleation in the PMMA/TPU increases as the saturation pressure increases. Regarding the effect of the foaming conditions, it is proved that it is necessary to have a fine control to avoid degeneration of the cellular materials. Graded nanocellular polymers with relative densities of 0.16–0.30 and cell sizes ranging 310–480 nm (in the nanocellular core) are obtained.

More people, more cities; the energy demand increases in consequence and much of that will rely on next-generation smart materials. Zn-ferrites (ZnFe2O4) are nonconventional ceramic materials on account of their unique properties, such as chemical and thermal stability and the reduced toxicity of Zn over other metals. Furthermore, the remarkable cation inversion behavior in nanostructured ZnFe2O4 extensively cast-off in the high-density magnetic data storage, 5G mobile communication, energy storage devices like Li-ion batteries, supercapacitors, and water splitting for hydrogen production, among others. Here, we review how aforesaid properties can be easily tuned in various ZnFe2O4 nanostructures depending on the choice, amount, and oxidation state of metal ions, the specific features of cation arrangement in the crystal lattice and the processing route used for the fabrication.

In this work, the fabrication of [Fe(pz)Pt(CN)4] (pz = pyrazine) thin films by means of matrix‐assisted pulsed laser evaporation (MAPLE) was investigated. As starting material, a cryogenically cooled suspension of nanocrystalline [Fe(pz)Pt(CN)4] (0.35wt.‐%) in a mixture of 1,1‐dichloroethane and polyethylene glycol (PEG) was used. Films of a thickness up to 150–200 nm were deposited on Si substrates by laser ablation at λ = 1064 nm of the cryogenically cooled material. PEG impregnated films exhibit a cooperative first‐order hysteretic spin crossover behavior around 155 K as detected by Raman spectroscopy. Most interestingly, deposition of a crystalline material was achieved through MAPLE deposition. [ABSTRACT FROM AUTHOR]

Abstract Low-density nanocellular polymers are required to take advantage of the full potential of these materials as high efficient thermal insulators. However, their production is still a challenging task. One promising approach is the use of nanostructured polymer blends of poly(methyl methacrylate) (PMMA) and a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM), which are useful for promoting nucleation but seem to present a severe drawback, as apparently avoid low relative densities. In this work, new strategies to overcome this limitation and produce low-density nanocellular materials based on these blends are investigated. First, the effect of very low amounts of the MAM copolymer is analysed. It is detected that nanostructuration can be prevented using low copolymer contents, but nucleation is still enhanced as a result of the copolymer molecules with high CO 2 affinity dispersed in the matrix, so nanocellular polymers are obtained using very low percentages of the copolymer. Second, the influence of the foaming temperature is studied. Results show that for systems in which there is not a clear nanostructuration, cells can grow more freely and smaller relative densities can be achieved. For these studies, blends of PMMA with MAM with copolymer contents from 10 wt% and as low as 0.1 wt% are used. For the first time, the production strategies proposed in this work have allowed obtaining low density (relative density 0.23) nanocellular polymers based on PMMA/MAM blends. Graphical abstract Image 1 Highlights • Low-density nanocellular polymers based on PMMA/MAM blends are produced. • Low MAM copolymer contents, as low as 0.1 wt%, are used to produce such materials. • The physical mechanisms that allow this reduction of the density are discussed. [ABSTRACT FROM AUTHOR]

The prompt management of patients with massive burns is essential to maximize survival by preventing infection, hemorrhage, fluid and heat loss, and to optimally prepare the wound bed for the application of autografts or cultured tissue-engineered artificial autologous skin. Acute treatments are typically based on temporary bio-dressings, commonly cadaveric skin allografts, but supply challenges, high costs and increasingly stringent regulatory requirements preclude their widespread use. Nanostructured fibrin-agarose hydrogels (NFAH) have been proven to be safe and effective biomaterials in preclinical and clinical studies, and show good hemostatic and biomechanical properties. Here we generated and tested NFAH with embedded allogeneic dermal fibroblasts (NFAH-F) under Good Manufacturing Practice (GMP) conditions. Fibroblasts were first expanded and characterized to create a GMP bank and the NFAH-F was manufactured on demand. Three patients with major burns were treated with this product as a temporary bio-dressing under compassionate use. Our results suggest that NFAH-F product was a safe product and no adverse reactions were observed. In all cases, the patients survived until definitive treatment. Therefore, the application of NFAH-F might be a temporary bio-dressing for patients with massive burns when cadaveric skin allografts are not available. [Display omitted] • Fibroblasts were efficiently expanded and banked under GMP compliant conditions. • A bio-dressing based on nanostructured fibrin-agarose hydrogels with embedded allogeneic fibroblasts (NFAH-F) was designed. • Three massively burned patients were treated with NFAH-F under compassionate use and no adverse reactions were observed. • The application of NFAH-F might be a temporary bio-dressing for patients when cadaveric skin allografts are not available. [ABSTRACT FROM AUTHOR]

The recent advances in the supramolecular control in nanostructured films have improved the performance of organic-based devices. However, the effect of different supramolecular arrangement on the sensor or biosensor performance is poorly studied yet. In this paper, we show the role of the composition and nanostructuration of the films on the impedance and voltammetric-based sensor performance to catechol detection. The films here studied were composed by a perylene derivative (PTCD-NH2) and a metallic phthalocyanine (FePc), using Langmuir-Blodgett (LB) and physical vapor deposition (PVD) techniques. The deposition technique and intrinsic properties of compounds showed influence on electrical and electrocatalytic responses. The PVD PTCD-NH2 shows the best sensor performance to the detection of catechol. Quantification of catechol contents in mate tea samples was also evaluated, and the results showed good agreement compared with Folin-Ciocalteu standard method for polyphenol detection.

Organic polymers can be made porous via continuous or discontinuous expansion processes in scCO2. The resulting foams properties are controlled by the interplay of three groups of parameters: (i) Chemical, (ii) physico-chemical, and (iii) technological/process that are explained in this paper. The advantages and drawbacks of continuous (extrusion, injection foaming) or discontinuous (batch foaming) foaming processes in scCO2, will be discussed in this article; especially for micro or nano cellular polymers. Indeed, a challenge is to reduce both specific mass (e.g., ρ < 100 kg·m−3) and cell size (e.g., average pore diameter ϕaveragepores < 100 nm). Then a particular system where small “objects” (coreshells CS, block copolymer MAM) are perfectly dispersed at a micrometric to nanometric scale in poly(methyl methacrylate) (PMMA) will be presented. Such “additives”, considered as foaming aids, are aimed at “regulating” the foaming and lowering the pore size and/or density of PMMA based foams. Differences between these additives will be shown. Finally, in a PMMA/20 wt% MAM blend, via a quasi one-step batch foaming, a “porous to nonporous” transition is observed in thick samples. A lower limit of pore size (around 50 nm) seems to arise.

Block copolymers have gained tremendous interest from the scientific community in the last two decades. These macromolecular architectures indeed constitute ideal nanostructured precursors for the generation of nanoporous materials meant for various high added value applications. The parallel emergence of controlled polymerization techniques has notably enabled to finely control their molecular features to confer them with unique structural and physicochemical properties, such as low dispersity values ( Đ ), well-defined volume fractions, and controlled functionality. The nanostructuration and ordering of diblock or triblock copolymers, which can be achieved through various experimental techniques, including channel die processing, solvent vapor or thermal annealing, nonsolvent-induced phase separation or concomitant self-assembly, and nonsolvent-induced phase separation, allows for the preparation of orientated microphase-separated copolymers whose morphology is dictated by three main factors, i.e., Flory-Huggins interaction parameter between constitutive blocks, volume fraction of the blocks, and polymerization degree. This review article provides an overview of the actual state of the art regarding the preparation of functional nanoporous materials from either diblock or triblock copolymers. It will also highlight the major applications of such peculiar materials.

Abstract The development of new high performance materials faces the challenge of implementing low temperature densification processes to overcome current technological limitations. In this context, the hydrothermal sintering, inspired by the natural processes of geological and biological mineralization, has recently emerged as a major opportunity to develop new and/or optimized materials that respond to today's scientific, technological and related socio-economic issues. The purpose of this viewpoint paper is to present opinions and propose future outlook for hydrothermal sintering based on the most recent achievements. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Raman spectra of soot particles were monitored in the gaseous flow extracted from the burning regions of two low-pressure premixed ethylene flames, for the first time. The flame conditions were chosen to explore the diversity of soot nanostructure in slightly sooting flames. Evaluation of the Raman spectral parameters revealed that the soot particles exhibited a strongly disordered structure and a large proportion of sp hybridization of the carbon. The appearance of sp carbon chains composing up to 30% of the total carbon content as well as an olefinic component may indicate their important role in soot nucleation and growth in low pressure ethylene flames. Hence, Raman spectroscopy of soot particles in the aerosol phase revealed that accretion and cyclization of the aliphatic carbon including sp carbon chains could thus be of importance for the initial soot growth and require more investigation. [ABSTRACT FROM AUTHOR]

Abstract Nanostructured polymer blends with CO2-philic domains can be used to produce nanocellular materials with controlled nucleation. It is well known that this nanostructuration can be induced by the addition of a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM) to a poly(methyl methacrylate) (PMMA) matrix. However, the effect of the block copolymer molecular weight on the production of nanocellular materials is still unknown. In this work, this effect is analysed by using three types of MAM triblock copolymers with different molecular weights, and a fixed blend ratio of 90 wt% PMMA and 10 wt% of MAM. Blends were produced by extrusion. As a result of the extrusion process, a non-equilibrium nanostructuration takes place in the blends, and the micelle density increases as MAM molecular weight increases. Micelle formation is proposed to occur as result of two mechanisms: dispersion, controlled by the extrusion parameters and the relative viscosities of the polymers, and self-assembly of MAM molecules in the dispersed domains. On the other hand, in the nanocellular materials produced with these blends, cell size decreases from 200 to 120 nm as MAM molecular weight increases. Cell growth is suggested to be controlled by the intermicelle distance and limited by the cell wall thickness. Furthermore, a theoretical explanation of the mechanisms underlying the limited expansion of PMMA/MAM systems is proposed and discussed. Graphical abstract Image 1 Highlights • Nanocellular polymers based on PMMA/MAM blends are produced. • Nanostructuration of the blends depends on MAM molecular weight. • Then, MAM molecular weight can used as a tool to control the cellular structure. [ABSTRACT FROM AUTHOR]

A comparative study of the magnetization and static magnetic susceptibility of high-temperature superconductors (HTSC) YBa2Cu3Oy synthesized by two variants of the sol-gel method with different average sizes of crystallites 〈 D〉 ranging 0.4-2 μm has been performed in constant magnetic fields (Н ≤ 6 kOe). It has been shown that the different annealing temperatures and times, at which their crystal structure is formed, change both the average sizes of crystallites 〈D〉 and the sizes of the structural homogeneity regions 〈l〉 and, at the same time, the magnetic field penetration depth (λ) and the coherence length (ξ). As a result, such parameters as 〈D〉 ~ λ and 〈l〉 ~ ξ become comparable, leading to a change in the physical characteristics of HTSCs. It has also been shown that the superconducting transition temperature Tc determined from the measurements of magnetic characteristics in constant magnetic fields remains within values optimal for superconductivity (Tc ≈ 92 K) in the case of an optimal number (y) of oxygen atoms, which determine the levels of charge doping for a given compound. [ABSTRACT FROM AUTHOR]

The influence of the synthesis and sintering methods on the structural, microstructural, stoichiometry and thus the magnetocaloric properties of the La 0.7 Ca 0.3 MnO 3 compound has been thoroughly studied. Soft-chemistry (sol-gel and polyol) synthesis and spark plasma sintering (SPS) procedures, used to obtain nanostructured materials, were compared to the traditional ceramic ones. This work evidences that SPS treatment not only reduces the grain size but also leads to oxygen sub-stoichiometry. This entails a lower Mn 4+ content in the manganite, and probably heterogeneity in the Mn 4+ grain distribution, which have consequences on the magnetic and magnetocaloric properties: a lower maximum entropy variation which is compensated by a larger transition temperature range. The sample prepared by combining polyol soft-chemistry synthesis and SPS sintering displays a higher maximum relative cooling power value, equal to 70% of that of gadolinium, the most effective material for domestic magnetic refrigeration. [ABSTRACT FROM AUTHOR]

The Surface Enhanced Raman Scattering (SERS) has demonstrated its high efficiency to increase the Raman signal of chemical and biological species and to be able to observe and identify a very low quantity of molecules paving the way to the single molecule sensitivity. Its application to molecular detection is now intensively developed to set-up various kind of highly sensitive sensors. In this paper, we propose a review on the SERS technique and on its use as sensor for the detection of explosives, since it is of first importance in the framework of public safety. After a description of the SERS principle, we report on the different methods developed for such detection (substrates, detection principles…) and on the results obtained (targeted analytes, sensitivity, limit of detection…). We discuss all these results and compared them with other current analytical methods. [ABSTRACT FROM AUTHOR]

The Surface Enhanced Raman Scattering (SERS) is a powerful method to observe and detect a large panel of molecules. Through the highly enhanced Raman signal, it is possible to identify a very low concentration of molecules and to improve the limit of detection in sensor applications. In this paper, we propose a review on the use of SERS as sensor for the detection of food contaminants. We describe the different approaches and methods proposed in the literature for such detection as well as the main sensing characteristics provided by the use of this technique. All these results will be discussed and compared with other detection methods. [ABSTRACT FROM AUTHOR]

Here we report the optimization on the covalent grafting methodology of a tripod-shaped penta( p -phenylene), 1 , on alkynyl-terminated silicon surfaces, and the incorporation of an active theophylline derivative, 2 , for the specific immobilization of proteins. The tripodal molecule presents azide-terminal groups to be attached onto a silicon surface containing an alkynyl monolayer. Initially, compound 1 has been covalently incorporated on alkynyl-terminated Si wafers, by the copper catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC, a click reaction). The tripod density on the silicon surface is tuned by performing the CuAAC reaction at different concentrations of 1 , as well as under different experimental conditions (T, base, copper source, shaking). Then, tripod 1 -modified surface has also been biofunctionalized with 2 . The effective preparation of this silicon-modified surface allowed us to study the streptavidin immobilization on the surface. Characterization of the different surfaces has been carried out by X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Bright-Field Optical Transmission Microscopy (Confocal) techniques. We also include density functional theory (DFT) analysis of the organic structures to confirm the height-profile and the tripod-surface relative configuration extracted from AFM images. [ABSTRACT FROM AUTHOR]

Nanostructured metal surfaces have been known to exhibit properties that deviate from that of the bulk material. By simply modifying the texture of a metal surface, various unique optical properties can be observed. In this paper, we present a simple two step electrochemical process combining electrodeposition and anodization to generate black gold surfaces. This process is simple, versatile and up-scalable for the production of large surfaces. The black gold films have remarkable optical behavior as they absorb more than 93% of incident light over the entire visible spectrum and also exhibit no specular reflectance. A careful analysis by scanning electron microscopy reveals that these unique optical properties are due to their randomly rough surface, as they consist in a forest of dendritic microstructures with a nanoscale roughness. This new type of black films can be fabricated to a large variety of substrates, turning them to super absorbers with potential applications in photovoltaic solar cells or highly sensitive detectors and so on. [ABSTRACT FROM AUTHOR]

Abstract We report here the successful design of 0–3 type nanocomposites where 30 nm ferromagnetic metallically conducting cores of manganite La 0.66 Sr 0.34 MnO 3 (LSMO) are discretely distributed in an insulating silica matrix. Starting from LSMO@SiO 2 core@shell nanoparticles, hydrothermal sintering process was used as a low temperature densification route (300 °C, 350 MPa, 90 min) in presence of 0.2 M aqueous sodium hydroxide solution. This process based on a pressure solution creep in the contact zones between nanoparticles allows the design of complex microstructures preventing the grain growth of the cores and the formation of interphases between the cores and the matrix. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

CeF 3 is largely used due to its technological importance for applications in various domains such as photonics, sensors, energy and catalysis and its nanostructuration represents a real challenge. In this paper, we report on the novel and environmentally friendly synthetic route of monodisperse CeF 3 nanoparticles (NP) with a diameter of about 10 nm and a high surface area (≈130 m2 g−1) by a surfactant-free aqueous precipitation route at room temperature (yield ≈ 90%). The dispersion of the NP as a stable colloidal suspension allows to prepare for the first time 3D interconnected macroporous CeF 3 through the assembly of as-prepared NP and home-made poly(methyl methacrylate) (PMMA) beads as template. These Organized Porous Inorganic Fluorides (OPIF) materials have been deeply characterized at different synthesis stages by means of powder X-ray diffraction (XRD), N 2 sorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. CeF 3 OPIF present a macroporosity (pore diameter ≈ 200 nm) as well as well as intergranular mesoporosity emerging from the voids between the CeF 3 NP (D TEM ≈ 7 nm) composing the OPIF walls resulting in a surface area of 33 m2 g−1. The thermal stability under nitrogen of the CeF 3 crystal structure is increased for the 3D interconnected macroporous materials in comparison with the NP as the CeF 3 crystal structure remains stable until 550 °C for CeF 3 OPIF and only 400 °C for CeF 3 NP. Finally, the porous structuration of CeF 3 materials considerably slows down the crystallite growth during thermal treatment under nitrogen. The crystallite size of CeF 3 NP constantly increases from 10 nm (120 °C) to 30 nm (420 °C). At the opposite, the crystallite size of CeF 3 OPIF remains unchanged until 460 °C (17 nm). [Display omitted] • CeF 3 nanoparticles (NP) obtained by a surfactant-free aqueous precipitation route. • Preparation of 3D interconnected macroporous CeF 3. • Thermal stability of the crystal structure increased for macroporous CeF 3 vs. NP. • Porous structuration of CeF 3 slows down the crystal growth during thermal treatment. [ABSTRACT FROM AUTHOR]

A key factor for dental implant success is a good sealing between the implant surface and both soft (gum) and hard (bone) tissues. Surface nanotopography can modulate cell response through mechanotransduction. The main objective of this research was the development of nanostructured titanium (Ti) surfaces that promote both soft and hard tissue integration with potential application in dental implants. Nanostructured Ti surfaces were developed by electrochemical anodization—nanopores (NPs) and nanonets (NNs)—and characterized by atomic force microscopy, scanning electronic microscopy, and contact angle analysis. In addition, nanoparticle release and apoptosis activation were analyzed on cell culture. NP surfaces showed nanoparticle release, which increased in vitro cell apoptosis. Primary human gingival fibroblasts (hGFs) and human bone marrow mesenchymal stem cells (hBM-MSCs) were used to test cell adhesion, cytotoxicity, metabolic activity, and differentiation markers. Finally, cell orientation on the different surfaces was analyzed using a phalloidin staining. NN surfaces induced an oriented alignment of both cell types, leading in turn to an improved expression of differentiation markers. Our results suggest that NN structuration of Ti surfaces has great potential to be used for dental implant abutments to improve both soft and hard tissue integration.

Metal nanostructures are, nowadays, extensively used in applications such as catalysis, electronics, sensing, optoelectronics and others. These applications require the possibility to design and fabricate metal nanostructures directly on functional substrates, with specifically controlled shapes, sizes, structures and reduced costs. A promising route towards the controlled fabrication of surface-supported metal nanostructures is the processing of substrate-deposited thin metal films by fast and ultrafast pulsed lasers. In fact, the processes occurring for laser-irradiated metal films (melting, ablation, deformation) can be exploited and controlled on the nanoscale to produce metal nanostructures with the desired shape, size, and surface order. The present paper aims to overview the results concerning the use of fast and ultrafast laser-based fabrication methodologies to obtain metal nanostructures on surfaces from the processing of deposited metal films. The paper aims to focus on the correlation between the process parameter, physical parameters and the morphological/structural properties of the obtained nanostructures. We begin with a review of the basic concepts on the laser-metal films interaction to clarify the main laser, metal film, and substrate parameters governing the metal film evolution under the laser irradiation. The review then aims to provide a comprehensive schematization of some notable classes of metal nanostructures which can be fabricated and establishes general frameworks connecting the processes parameters to the characteristics of the nanostructures. To simplify the discussion, the laser types under considerations are classified into three classes on the basis of the range of the pulse duration: nanosecond-, picosecond-, femtosecond-pulsed lasers. These lasers induce different structuring mechanisms for an irradiated metal film. By discussing these mechanisms, the basic formation processes of micro- and nano-structures is illustrated and justified. A short discussion on the notable applications for the produced metal nanostructures is carried out so as to outline the strengths of the laser-based fabrication processes. Finally, the review shows the innovative contributions that can be proposed in this research field by illustrating the challenges and perspectives.

The heat capacity and thermal behavior trend along the 1-alkyl-3-methylimidazolium hexafluorophosphate [C n C 1 im][PF 6 ] (with n = 2–10, 12) ionic liquids series, is used to explore the effect of the alkyl chain length in the nanostructuration. The heat capacities of the studied ILs were measured with an uncertainty better than ± 0.15% and are in excellent agreement with the available data in the literature. An odd-even effect for the specific and volumic heat capacities of the [C n C 1 im][PF 6 ] series was found. The observed odd-even effect in the liquid heat capacity was rationalized considering the preferential orientation of the terminal CH 3 group. The higher specific/volumic heat capacities shown for the [C 6 C 1 im][PF 6 ] and [C 8 C 1 im][PF 6 ] are an indication of an additional conformational disorder increase in the liquid phase that could be related with a weaker alkyl chain interdigitation capability of the even number chain ILs. The melting temperatures and consequent ∆ s l H m o and ∆ s l S m o trend along the alkyl series present a V-shape profile that is explained based on the analysis of the balance between the initial decrease of the electrostatic interaction potential and the increase of the van der Waals interactions with the increasing size of the alkyl side chain of the cation. The inhibition of crystallization for intermediate alkyl chain size (from [C 5 C 1 im][PF 6 ] to [C 8 C 1 im][PF 6 ]) seems to arise from the overlapping of the hypothetical cold crystallization temperature by the melting temperature. Above the critical alkyl size, CAS, a regular increase in the entropy and enthalpy profiles presents a similar shape than the observed in other alkane series and is a strong support of the intensification of the ILs nanostructuration. [ABSTRACT FROM AUTHOR]

We investigated the fabrication of large-area (cm2) nanostructured glasses for solar cell modules with hydrophobic and hydrophilic properties using soft lithography and colloidal lithography. Both of these techniques entail low-cost and ease of nanofabrication. We explored the use of simple 1D and 2D nanopatterns (nanowires and nanocones) and the effect of introducing disorder in the nanostructures. We observed an increase in the transmitted light for ordered nanostructures with a maximum value of 99% for wavelengths >600 nm when ordered nanocones are fabricated on the two sides of the solar glass. They produced an increment in the efficiency of the packaged solar cell with respect to the glass without nanostructures. On the one hand, the wettability properties showed that the ordering of the nanostructures improved the hydrophobicity of the solar glasses and increased their self-cleaning capacity. On the other hand, the disordered nanostructures improved the hydrophilic properties of solar glasses, increasing their anti-fogging capacity. The results show that by selecting the appropriate nanopattern, the wettability properties (hydrophobic or hydrophilic) can be easily improved without decreasing the efficiency of the solar cell underneath. [ABSTRACT FROM AUTHOR]

A triblock copolymer (BCP) of the PS- b -PB- b -PS (SBS) type [PS: polystyrene, PB: polybutadiene] with cylindrical morphology containing pristine or PS-functionalised multi-walled carbon nanotubes (MWCNTs) was exposed to steady shear and large amplitude oscillatory shear (LAOS). Axis symmetric shear was applied in a rheometer for the orientation of the BCP cylinders and the alignment of MWCNTs within the BCP matrix. Neat SBS and SBS nanocomposites with 0.1 wt% of pristine MWCNTs ( p -CNT) and PS-grafted MWCNTs (PS-g-CNT) were prepared by solution mixing prior to the shear experiments. Small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) indicated long-range ordered BCP cylindrical nanodomains highly oriented and hexagonally packed in the case of LAOS. SBS/CNT-g-PS nanocomposite showed slightly disturbed BCP orientation, however well aligned CNTs in the direction of shear for LAOS conditions. The extent of ordering with respect to the different shear conditions and MWCNT surface functionalisation are elucidated. [ABSTRACT FROM AUTHOR]

In this work, the properties of cellulose (CE)/xyloglucan (XG) biopolymer blends are investigated, taking inspiration from the outstanding mechanical properties of plant cell walls. CE and XG were first co-solubilized in an ionic liquid, 1-ethyl-3-methylimidazolium acetate, in order to blend these biopolymers with a varying CE:XG ratio. The biopolymers were then regenerated together using water to produce solid blends in the form of films. Water-soluble XG persisted in the films following regeneration in water, indicating an attractive interaction between the CE and XG. The final CE:XG ratio of the blends was close to the initial value in solutions, further suggesting that intimate mixing takes place between CE and XG. The resulting CE/XG films were found to be free of ionic liquid, transparent and with no evidence of phase separation at the micron scale. The mechanical properties of the blend with a CE:XG ratio close to one revealed a synergistic effect for which a maximum in the elongation and stress at break was observed in combination with a high elastic modulus. Atomic force microscopy indicates a co-continuous nanostructure for this composition. It is proposed that the non-monotonous variation of the mechanical performance of the films with XG content is due to this observed nanostructuration. [ABSTRACT FROM AUTHOR]

The epitaxial graphene buffer layer on the Si face of hexagonal SiC shows a promising band gap, of which the precise origin remains to be understood. In this work, we correlate the electronic to the atomic structure of the buffer layer by combining angle resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM), and high-resolution scanning transmission electron microscopy (HR-STEM). We show that the band structure in the buffer has an electronic periodicity related to the structural periodicity observed in STM images and published X-ray diffraction. Our HR-STEM measurements show the bonding of the buffer layer to the SiC at specific locations separated by 1.5 nm. This is consistent with the quasi 6 × 6 periodic corrugation observed in the STM images. The distance between buffer C and SiC is 1.9 Å in the bonded regions and up to 2.8 Å in the decoupled regions, corresponding to a 0.9 Å corrugation of the buffer layer. The decoupled regions are sp² hybridized. Density functional tight binding (DFTB) calculations demonstrate the presence of a gap at the Dirac point everywhere in the buffer layer, even in the decoupled regions where the buffer layer has an atomic structure close to that of graphene. The surface periodicity also promotes band in the superperiodic Brillouin zone edges as seen by photoemission and confirmed by our calculations. [ABSTRACT FROM AUTHOR]

Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol-gel process using hexadecyltrimethoxysilane (C16TMS) and tetramethoxysilane (TMOS) (1:4 molar ratio) as precursors. After coating, silica nanoparticles (SiO2 NPs) functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC8MS) were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO2 NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO2 NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of hydrophobic SiO2 NPs showed that the degradation of the alkyl groups takes place in the 200-400°C range. Bilayer coating with C16TMS/TMOS and SiO2 NPs modified with alkoxysilane substituted with C8 alkyl chain (SiO2 NP-C8) has micro/nano structure. Hydrophobicity of functionalized SiO2 NPs-C8 and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C16TMS/TMOS + SiO2 NPs-C8 (145°), compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO2 NPs is useful for the modification of surface polarity and roughness. [ABSTRACT FROM AUTHOR]

Current tissue engineering technology focuses on developing simple tissues, whereas multilayered structures comprising several tissue types have rarely been described. We developed a highly biomimetic multilayered palate substitute with bone and oral mucosa tissues using rabbit cells and biomaterials subjected to nanotechnological techniques based on plastic compression. This novel palate substitute was autologously grafted in vivo, and histological and histochemical analyses were used to evaluate biointegration, cell function, and cell differentiation in the multilayered palate substitute. The three-dimensional structure of the multilayered palate substitute was histologically similar to control tissues, but the ex vivo level of cell and tissue differentiation were low as determined by the absence of epithelial differentiation although cytokeratins 4 and 13 were expressed. In vivo grafting was associated with greater cell differentiation, epithelial stratification, and maturation, but the expression of cytokeratins 4, 13, 5, and 19 at did not reach control tissue levels. Histochemical analysis of the oral mucosa stroma and bone detected weak signals for proteoglycans, elastic and collagen fibers, mineralization deposits and osteocalcin in the multilayered palate substitute cultured ex vivo. However, in vivo grafting was able to induce cell and tissue differentiation, although the expression levels of these components were always significantly lower than those found in controls, except for collagen in the bone layer. These results suggest that generation of a full-thickness multilayered palate substitute is achievable and that tissues become partially differentiated upon in vivo grafting. [ABSTRACT FROM AUTHOR]