Nanostructured biosilica produced by Thalassiosira weissflogii diatoms is covalently functionalized with the cyclic nitroxide 2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), an efficient scavenger of reactive oxygen species (ROS) in biological systems. Drug delivery properties of the TEMPO-functionalized biosilica are studied for Ciprofloxacin, an antimicrobial thoroughly employed in orthopedic or dental implant related infections. The resulting TEMPO-biosilica, combining Ciprofloxacin drug delivery with anti-oxidant properties, is demonstrated to be a suitable material for fibroblasts and osteoblast-like cells growth.

Diatoms microalgae produce biosilica nanoporous rigid outershells called frustules that exhibit an intricate nanostructured pore pattern. In this paper two specific Thalassiosira weissflogii culture conditions and size control procedures during the diatoms growth are described. Data from white field and fluorescence microscopy, evaluation of cell densities and cell parameters (k value and R value) according to cell culture conditions are listed. Different cleaning procedures for obtaining bare frustules are described. In addition, FTIR and spectrofluorimetric analyses of cleaned biosilica are shown. The data are related to the research article"Chemically Modified Diatoms Biosilica for Bone Cell Growth with Combined Drug-Delivery and Antioxidant Properties" [1].

The atmospheric pressure plasma deposition of hydroxyl functionalized hydrocarbon films is reported in this work, with a reactor fed with water aerosol and ethylene. The effects of power and feed flow rates onto film chemistry have been investigated. Coatings produced with this approach can find application in the biomedical field, among others, as platforms for cell adhesion and proliferation. Results show that operating at 4 kHz provides a much higher amount of hydroxyl group in the coating compared with samples obtained at 11 kHz. After water immersion, the stability of the films and their amount of hydroxyl groups remain high. A simplified deposition mechanism is proposed.

Bio-composite coatings, consisting of an organic matrix embedding a bioactive molecule, have been deposited by means of atomizer-assisted atmospheric pressure plasma. Ethylene was chosen as the precursor of the matrix, while the atomizer was fed with a water solution of lysozyme. Coatings chemical composition was investigated by XPS, FTIR and MALDI-TOF spectroscopies, and it has been proved that the one-step inclusion of protein domains in the composite coatings is successful and lysozyme chemical structure is only slightly altered. The amount of embedded lysozyme is as high as 14?g/cm² as evaluated from water release test. Finally, the activity of the plasma-embedded protein is close to that of pure lysozyme as verified against Micrococcus lysodeikticus ATCC 4698 through an agar plate diffusion test.

In this work, the role of a chemical parameter, such as the degree of fluorination, on the wetting behavior ofnanotextured hydrophobic surfaces is investigated. Texture and chemistry tuning of the surfaces has been accomplishedwith single batch radiofrequency low-pressure plasma processes. Polystyrene substrates have been textured by CF4plasma etching and subsequently covered by thin films with a tunable F-to-C ratio, obtained in discharges fed withC4F8-C2H4. Measurements of wetting dynamics reveal a regime transition from adhesive-hydrophobic to slipperysuperhydrophobic,i.e., from wet to non wet states, as the F-to-C rises at constant topography. Such achievements arestrengthened by calculation of the solid fraction of surface water contact area applying Cassie-Baxter advancing andreceding equations to water contact angle data of textured and flat reference surfaces

Antifog surfaces are necessary for any application requiring optical efficiency of transparent materials. Surface modification methods aimed toward increasing solid surface energy, even when supposed to be permanent, in fact result in a nondurable effect due to the instability in air of highly hydrophilic surfaces. We propose the strategy of combining a hydrophilic chemistry with a nanotextured topography, to tailor a long-lasting antifog modification on commercial transparent plastics. In particular, we investigated a two-step process consisting of self-masked plasma etching followed by plasma deposition of a silicon-based film. We show that the deposition of the silicon-based coatings on the flat (pristine) substrates allows a continuous variation of wettability from hydrophobic to superhydrophilic, due to a continuous reduction of carbon-containing groups, as assessed by Fourier transform infrared and X-ray photoelectron spectroscopies. By depositing these different coatings on previously nanotextured substrates, the surface wettability behavior is changed consistently, as well as the condensation phenomenon in terms of microdroplets/liquid film appearance. This variation is correlated with advancing and receding water contact angle features of the surfaces. More importantly, in the case of the superhydrophilic coating, though its surface energy decreases with time, when a nanotextured surface underlies it, the wetting behavior is maintained durably superhydrophilic, thus durably antifog.

The electrical transport across a biomimetic interface made up of spin coated melanin layers on nanotextured silicon surfaces with different texturing features and wetting properties is discussed. Nanotexturing allows, under certain conditions, the melanin to anchor better on a hydrophobic silicon surface, overcoming the hydrophilic melanin-hydrophobic silicon interface issue. The feature of the electrical signal transduction across such a structure was studied by impedance spectroscopy and found to be influenced by the nano-texturing chemistry and surface morphology. The effects of a voltage pulse, as external stimulus modifying the electrical transport mechanisms, and retention of the subsequently achieved carrier transport conditions have been elucidated. The results suggest a possible exploiting of this circuit element for bio and environmental molecules' sensing.

Plasma Processes and Polymers

The reflectivity of transparent polymers can be reduced with a proper nanotextured layer on the surface according to the moth eye effect. Plasma etching has been proved to be a reliable method to generate self-organized nanostructures on the surface of various polymers. In the present work this method, directly carried out in one step, has been tested on polycarbonate for application as low reflective transparent material. CF4 and O2 fed plasma processes have been compared at different treatment time. Chemical (X-ray photoelectron spectroscopy), morphological (scanning electron microscopy), and optical (diffuse and specular reflectance, normal and grazing incidence) features have been evaluated. Results indicate that the CF4-to-O2 feed ratio significantly affects shape and distribution of the generated structures. O2 plasma, in particular, leads to taller structures with wire-like aspect and more homogeneous distribution, which are more effective in reducing reflectance with a broadband character (visible and near-infrared). Treatment duration, which instead affect mainly the dimension scale of the structures, must be tailored in order to control diffuse component of reflectance.

Silicon dioxide-like barrier films were deposited by plasma enhanced chemical vapor deposition fromdifferent siloxane and silane precursors. The variation of the precursor was investigated as a route to obtainsilicon dioxide-like films with different structures, densities and hence barrier performances.Although the films were characterized by the same elemental composition, some differences in film densityand porosity were evidenced from optical properties measurements and from the shift of the SiOSi infraredabsorption band position. These differences were correlated with film microstructure and in turn withbarrier performances. The results confirmed that films with high density and low porosity performed betteras single inorganic barrier layers for food-packaging

In this paper a single step process for the synthesis of composite thin films made of platinum nanoclusters embedded in a porous hydrocarbon matrix is proposed. The process consists of a simultaneous plasma enhanced-chemical vapour deposition of ethylene and sputtering of a platinum target. Films were characterized by means of Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Optical emission spectroscopy was used to investigate the plasma phase and to find correlations with the metal content of the film. The effect of radio frequency power, deposition time, and ethylene flow rate on the chemical composition and structure of the film is presented. Results show that the platinum content in the film can be controlled by tuning the power delivered to the plasma and the monomer flow rate, and that the metal aggregates in crystalline nanoclusters uniformly distributed in the material. Film morphology is characterized by columnar structures of variable diameter and orientation depending on the deposition conditions.

The alternated deposition of silicon oxide and organosilicon layers, yielding to ultra-barrier films against the transmission of vapors and gases through plastic substrates, has been demonstrated to be also an effective tool for the deposition of highly corrosion protective coatings on low-carbon steel substrate. PECVD is really efficient for the deposition of multilayered stacks since it allows the deposition of the organosilicon and silicon oxide layers in the same process chamber and using the same precursor, the tetraethoxysilane. The multilayer approach leads to 600-nm-thick coatings with high corrosion resistance (1.1 x 10(7) Omega cm(2)), while a layer of SiO(x) has the same protective effectiveness only for thickness greater than 1 mu m. The use of modulated discharges for the multilayer deposition exhibits an improved resistance to corrosion by two orders of magnitude with respect to continuous mode.

High performance electrocatalytic hydrocarbon thin films containing Pt nano-clusters are deposited bysimultaneous plasma polymerization of ethylene and sputtering of a Pt target. The proposed syntheticapproach largely simplifies the PEMFC electrocatalyst fabrication process with respect to conventionalmethods. The deposition of the hydrocarbon matrix provides the mechanical support and electroniccontinuity, ensuring a uniform metal dispersion, avoiding Pt nanoparticle agglomeration. The Ptcatalyst is dispersed as small vertically stacked clusters with size less than 10 nm in columnar thin(250-500 nm) films. PEMFC testing with plasma deposited 500 nm thick film and 0.513 mg cm2 Pt loadas anodic electrocatalyst led to a maximum reproducible power density as high as 300 mW cm2.

Herein, plasma deposited thermally responsive thin polymer films from N-vinylcaprolactam (NVCL) is reported for the first time by using a low pressure RF plasma process. While FT-IR and XPS analyses highlight the film chemistry, ToF-SIMS combined with MALDI-MS analyses allow to accurately identify different oligomer distributions in the deposited film. The switching behavior of these smart surfaces is confirmed with water contact angle measurements at low and high temperatures, allowing also to estimate the Lower Critical Solution Temperature.

In this paper, we present a one step plasma based approach for the deposition of Pt-fluorocarbon nanocomposite films as electrocatalysts in hydrogen-based micro fuel cells. Results show that the chemical and morphological structure of the film can be tuned by controlling the power delivered to the plasma, and the gas feed composition. Platinum is included in the film in metallic form and its content can be continuously varied from a few atomic percent to 86%. The metal is embedded in the film as crystalline nanoclusters of size below 10 nm, uniformly distributed across the sample. Film catalytic activity, in terms of hydrogen oxidation reaction, has been tested by cyclovoltammetry and it increases with the Pt loading, with a maximum specific electrochemical surface area of 94cm(2) center dot mg(-1), for film deposited on flat glassy carbon.

A novel technique, combining the plasma assisted deposition of Si Ox-like coatings with the initiated chemical vapor deposition (iCVD) of organosilicon films in a single-chamber process, was investigated for the production of multistack barriers against the water vapor permeation. Hexavinyldisiloxane (HVDSO) was used as the film precursor for both kinds of polymerization. iCVD of HVDSO resulted in highly crosslinked and adherent carbon-rich polymer which reduced the substrate roughness of the substrate, thus acting as a primer for the deposition of the denser C-depleted uplayer. The plasma ion bombardment of the C-rich underlayer produced a graded interphase which enhanced the adhesion between the layers and of the multilayer stack to the polymer substrate. The C-rich interlayers effectively decoupled the defects of the C-depleted layers, indeed a barrier improvement factor of 100 over the single C-depleted barrier layer was obtained with a hexalayer structure.

Reactive ion etching (RIE) plasma processes fed with CF4 have been investigated as single-step maskless method for nanotexturing the surface of crystalline silicon. Variation of surface topography under different plasma conditions has been evaluated with scanning electron microscopy and correlated with total, diffuse, and specular reflectance. Chemical features have been evaluated by X-ray photoelectron spectroscopy and current-voltage characteristics have been measured under dark and illuminated conditions. Results indicate that a widely tunable nanoscale texture can be generated onto silicon surface leading to a reduced total reflectance. A significant uptake of carbon and fluorine is detected onto treated silicon with fluorine mainly in ionic form. Further, the plasma modification is per se capable, without further doping procedures, to generate a photovoltaic behavior onto treated silicon, with higher short circuit current in less reflective samples.

Surface engineering has been explored using plasma enhanced chemical vapur deposition (PECVD) of SiO2-like coatings on different metallic substrates in order to improve their resistance to corrosion. Specifically, the coatings have been deposited onto silver-based alloys which are prone to unaesthetic tarnishing, by means of PECVD in radio frequency (RF) plasma fed with tetraetoxysilane/oxygen/argon mixture. Microchemical and microstructural characterization of the coatings has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The protective effectiveness against tarnishing of SiO2-like layers has been evaluated by immersion tests in 0.1M Na2S aerated solution at room temperature. It has been found that SiO2-like coatings deposited by increasing the oxygen-to-monomer ratio in the feeding-gas mixture and the input power density possess excellent barrier effects, and the coating adhesion increases if the deposition process is performed after a hydrogen plasma treatment. The protective effectiveness of PECVD coatings may be related to their barrier effect against the diffusion of water and other gaseous aggressive agents present in the environment and coming into contact with the metal surface. Copyright (C) 2010 John Wiley & Sons, Ltd.

This work enlighten on the modification of the electrical and optoelectronic properties at metal/silicon interface, where the silicon surface is nanostructured by single step mask-less CF4 plasmain reactive ion etching mode. The electrical transport across metal/nanotextured silicon/siliconstructure has been correlated with morphological variations of surface topological features andchemistry. The results evidence that such nanostructures enhance the photovoltaic behavior andaffect electrical and optoelectronic transport to a different extent, depending not only on surfacetexturing but also on surface chemistry.

Au nanoparticles (NPs) self-assembled by means of a simple solvent evaporation strategy in a two-dimensional (2D) superlattice with a highly controlled geometry and extending over micrometers squared when drop cast onto a suitably functionalized silicon substrate. The assembly procedure was defined by carefully monitoring experimental parameters, namely, dispersing solvent, deposition temperature, Au NP concentration, and chemistry of supporting substrate. The investigated parameters were demonstrated to play a significant role on the delicate energetic balance of the mutual NPs as well as NP-substrate interactions, ultimately directing the NP assembly. Remarkably, substrate surface chemistry revealed to be decisive to control the extent of the organization. Scanning electron microscopy demonstrated that the 2D superlattice extends uniformly over hundreds of square micrometers. Grazing-incidence small-angle X-ray scattering investigation validated the Au NP organization in crystalline domains and confirmed the role played by the surface chemistry of the substrate onto the 2D lattice assembly. Finally, preliminary spectroscopic ellipsometry investigation allowed extraction of optical constants of NP assemblies. The localized surface plasmon resonance modes of the NP assemblies were studied through a combined analysis of reflection, transmission, and ellipsometric data that demonstrated that the plasmonic properties of the Au NP assemblies strongly depend on the substrate, which was found to influence NP ordering and near-field interactions between NPs. © 2014 American Chemical Society.

The invention relates to a method for manufacturing a proton conductive membrane. The method of the invention comprises the following steps: a) depositing on said surface of said substrate a layer of polymer material by hot wire chemical vapour deposition starting from a gaseous mixture comprising: at least two monomers having the following formula (I): RFyOzA02X wherein: A is P or S; X is F or C1; 1 ≤ y ≤ 25; 0 ≤ z ≤ 6; R is a C1-C25, saturated or unsaturated, linear or branched, alkyl chain optionally comprising a cyclic or aromatic group, and a polymerisation initiator, and b) hydrolysis of the layer of polymer obtained in step a). The invention is usable in the field of storage and restitution of energy, in particular.

The catalyst thin layer consists of electronically conductive catalyst nano-particles embedded in a polymeric matrix. The ratio number of catalyst atoms/total number of atoms in the catalyst layer is comprised between 40% and 90%, more preferably between 50% and 60%.

An optical element includes a body (6) made of transparent plastic material and at least one of the surfaces is modified in order to present a plurality of nanostructures (7) obtained directly onto the surface (5, 5') of the body (6); the nanostructured surface is at least partly coated with a film (15) of an hydrophilic material, preferably inorganic, and has superhydrophilic properties that are stable in time.