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Composites fabricated by metal nanoparticles supported on graphene sheets are promising for many technological applications ranging from sensing, energy production and storage, catalysis to electronics and optoelectronics. This is due to the benefits offered by the properties of both components. In particular, charge transfer effects at graphene-nanoparticles interface are the basis for the operation of several devices. Here we present an approach to fabricate hybrid composites consisting of graphene-noble metal nanoparticles. Mono- and bimetallic platinum and palladium nanoparticles are produced by laser ablation in a liquid environment and their morphology is characterized by transmission electron microscopy. In addition, in order to fabricate low-dimensional hybrid composites, the nanoparticles are loaded on graphene layer by spin coating of colloidal solutions and the density of the nanoparticles on graphene was evaluated by scanning electron microscopy. The nanoparticles-graphene charge transfer was studied by employing Raman spectroscopy and conductive atomic force microscopy. In particular, the degree of the G and 2D Raman peak shifts (evidenced by the Raman Spectroscopy measurements) and the characteristics of the current-voltage curves (evidenced by conductive atomic force microscopy) allowed inferring an n-type doping effect of the metal nanoparticles on the graphene properties, i. e. electrons transfer from the nanoparticles to the graphene layers. A combined analysis of these results allow us to demonstrate that the chemical composition of the metal nanoparticles is a key parameter in determining the charge transfer phenomenon in low-dimensional systems.

The assembly behaviour of amphiphilic poly(styrene)-block-poly(t -butyl acrylate) block copolymer at air/water interface has been studied in view of its ability to form condensed phases. The film, transferred by Horizontal Precipitation Langmuir-Blodgett method without modifications, has been studied. Chemical imaging unravels the orientation of the condensed phases and, once defined their chemical orientation, the morphology of the block copolymer film and the pressure-induced growth processes have been investigated by Atomic Force Microscopy . Micelles and flat regions, 1 nm thick, were found. The micelles growth mechanism is interpreted as a coalescence process, allowing to predict the pressure-induced evolution of the chemical microphases.

Mono-metallic and bi-metallic Palladium and Platinum nanoparticles find important applications for sensing detection, catalysis, hydrogen storage, fuel cell etc. However, the success of such technologies is subjected to the development of simple, versatile, low-cost, high-throughput methods for the production of the nanoparticles with desired sizes or composition. In particular, we present a laser-assisted synthesis method for the production of stable mono- and bi-metallic Pd and Pt nanoparticles. It is based on the nanosecond-pulsed laser ablation, in liquid environment, of pure Pd or Pt targets and of PtPd composite target at different ablation times. We characterized nanoparticles’ morphology and crystalline structure by Transmission Electron Microscopy, Selected Area Electron Diffraction, X-Ray Diffraction and Energy Dispersive X-Ray measurements. In particular, the microscopic analysis showed that the average diameter of the nanoparticles is around 10–15 nm. The stability of the solutions was checked by UV–vis spectroscopy. Furthermore, by Scanning Transmission Electron Microscopy we found that, in bimetallic nanoparticles, Pt and Pd are homogeneously distributed on the whole volume of particle. In addition, we used the produced nanoparticles to decorate graphene layers by simple spin coating of the colloidal solutions onto the substrates, obtaining nanoparticles/Graphene nanocomposites with a “starry sky” type morphology. Also, trough Scanning Electron Microscopy images, the surface density of the nanoparticles on graphene was evaluated. We establish, therefore, a general working framework for the controlled nanofabrication of nanoparticles/graphene nanocomposites that could find interesting applications in catalysis and in electronic devices.

Today, nanophotonics still lacks components for modulation that can be easily implementable in existing siliconon-insulator (SOI) technology. Chalcogenide phase change materials (PCMs) are promising candidates for tuning in the near infrared: at the nanoscale, thin layers can provide enough contrast to control the optical response of a nanostructure. Moreover, all-dielectric metamaterials allow for resonant behavior without having ohmic losses in the telecom range. Here, a novel hybridization of a SOI-based metamaterial with PCM GeTe is experimentally investigated. A metamaterial based on Si nanorods, covered by a thin layer of GeTe, is designed and fabricated. Switching GeTe from amorphous to crystalline leads to a rather high resonance-governed reflection contrast at 1.55 mu m. Additional confocal Raman imaging is done to differentiate the crystallized zones of the metamaterials' unit cell. The findings are in good agreement with numerical analysis and show good perspectives of all-dielectric tunable near-infrared nanophotonics. (C) 2019 Optical Society of America

Pd and Pt nanoparticles on Fluorine-doped tin oxide (FTO) are produced. This outcome is reached by processing nanoscale-thick Pd and Pt films deposited on the FTO surface by nanosecond laser pulse. Such laser processes are demonstrated to initiate a dewetting phenomenon in the deposited metal films and lead to the formation of the nanoparticles. In particular, the effect of the film&rsquo, s thickness on the mean size of the nanoparticles, when fixed the laser fluence, is studied. Our results indicate that the substrate topography influences the dewetting process of the metal films and, as a consequence, impacts on the nanoparticle characteristics. The results concerning the Pd and Pt nanoparticles&rsquo, sizes versus starting films thickness and substrate topography are discussed. In particular, the presented discussion is based on the elucidation of the effect of the substrate topography effect on the dewetting process through the excess of chemical potential. Finally, Raman analysis on the fabricated samples are presented. They show, in particular for the case of the Pd nanoparticles on FTO, a pronounced Raman signal enhancement imputable to plasmonic effects.

Submicron-thick Ag films were sputter deposited, at room temperature, on Si, covered by the native SiO2 layer, and on Ti, covered by the native TiO2 layer, under normal and oblique deposition angle. The aim of this work was to study the morphological differences in the grown Ag films on the two substrates when fixed all the other deposition parameters. In fact, the surface diffusivity of the Ag adatoms is different on the two substrates (higher on the SiO2 surface) due to the different Ag-SiO2 and Ag-TiO2 atomic interactions. So, the effect of the adatoms surface diffusivity, as determined by the adatoms-substrate interaction, on the final film morphology was analyzed. To this end, microscopic analyses were used to study the morphology of the grown Ag films. Even if the homologous temperature prescribes that the Ag film grows on both substrates in the zone I described by the structure zone model some significant differences are observed on the basis of the supporting substrate. In the normal incidence condition, on the SiO2/Si surface a dense close-packed Ag film exhibiting a smooth surface is obtained, while on the TiO2/Ti surface a more columnar film morphology is formed. In the oblique incidence condition the columnar morphology for the Ag film occurs both on SiO2/Si and TiO2/Ti but a higher porous columnar film is obtained on TiO2/Ti due to the lower Ag diffusivity. These results indicate that the adatoms diffusivity on the substrate as determined by the adatom-surface interaction (in addition to the substrate temperature) strongly determines the final film nanostructure.

Pd films were deposited, at room temperature, on Ti and SiO 2 substrates by normal (0°) and oblique (36° and 48°) incidence sputtering processes. Scanning electron microscopy was used to analyze the surface and cross morphology of the Pd films so to study the effect of the Pd adatoms surface diffusivity on the films nanostructure. In fact, even if the low homologous temperature (0.17) prescribes that the Pd film grows on both substrates in the Zone I of the structure zone model, some differences are observed: in normal incidence condition, the Pd film on the Ti substrate was found to be formed by tapered grains, while on the SiO 2 substrate the Pd film exhibited a columnar morphology with the columns showing a cauliflower shape. Also in the oblique deposition configurations, notable differences in the nanoscale morphology of the Pd films grown in the same conditions are observed on the basis of the supporting substrate. These data suggest that, during depositions, the Pd adatoms diffusivity on the substrate, as determined by the film-substrate interaction both in normal and oblique deposition conditions, is crucial in determining the final film nanostructure. This aspect is semi-quantitatively discussed on the basis of the adsorption energy of the Pd atoms on Ti (0.69 eV) and on SiO 2 (0.27 eV).

Nanoporous Au attracts great technological interest and it is a promising candidate for optical and electrochemical sensors. In addition to nanoporous Au leafs and films, recently, interest was focused on nanoporous Au micro- and nano-structures on surfaces. In this work we report on the study of the characteristics of nanoporous Au structures produced on surfaces. We developed the following procedures to fabricate the nanoporous Au structures: we deposited thin Au/Ag bilayers on SiO 2 or FTO (fluorine-doped tin oxide) substrates with thickness x Au and x Ag of the Au and Ag layers; we induced the alloying and dewetting processes of the bilayers by furnace annealing processes of the bilayers deposited on SiO 2 and by laser irradiations of the bilayers deposited on FTO; the alloying and dewetting processes result in the formation of Au x Ag y alloy sub-micron particles being x and y tunable by x Au and x Ag . These particles are dealloyed in HNO 3 solution to remove the Ag atoms. We obtain, so, nanoporous sub-micron Au particles on the substrates. Analyzing the characteristics of these particles we find that: a) the size and shape of the particles depend on the nature of the dewetting process (solid-state dewetting on SiO 2 , molten-state dewetting on FTO); b) the porosity fraction of the particles depends on how the alloying process is reached: about 32% of porosity for the particles fabricated by the furnace annealing at 900 °C, about 45% of porosity for the particles fabricated by the laser irradiation at 0.5 J/cm 2 , in both cases independently on the Ag concentration in the alloy; c) After the dealloying process the mean volume of the Au particles shrinks of about 39%; d) After an annealing at 400 °C the nanoporous Au particles reprise their initial volume while the porosity fraction is reduced. Arguments to justify these behaviors are presented.

A poly(p-phenyleneethynylene) polymer (PCF[5]), bearing two π-rich cone-like calix[5]arene cavities (assembling cores) attached to a rigid p-phenyleneethynylene spacer, was synthesised by a Pd-catalysed cross-coupling reaction. UV–vis absorption and fluorescence spectroscopies combined with dynamic light scattering measurements provide evidence for the self-assembly of PCF[5] (homopolytopic host molecule) with a complementary C60 fulleropyrrolidine (C60-Pyr) guest in solution, in the construction of a supramolecular polymer network. Atomic force microscopy analysis of PCF[5]/C60-Pyr highlights the formation of a bicontinuous network consisting of a uniform distribution of prominent structures, within a polymeric background forming a biphasic structure.

We present a study on the fraction of porosity for dealloyed nanoporous Au leafs. Nanoporous Au is attracting great scientific interest due to its peculiar plasmonic properties and the high exposed surface (∼10 m 2 /g). As examples, it was used in prototypes of chemical and biological devices. However, the maximization of the devices sensitivity is subjected to the maximization of the exposed surface by the nanoporous Au, i. e. maximization of the porosity fraction. So, we report on the analyses of the porosity fraction in nanoporous Au leafs as a function of the fabrication process parameters. We dealloyed 60 μm-thick Au 23 Ag 77 at.% leafs and we show that: a) for dealloying time till to 6 h, only a 450 nm-thick surface layer of the leafs assumes a nanoporous structure with a porosity fraction of 32%. For a dealloying time of 20 h the leafs result fragmented in small black pieces with a porosity fraction increased to 60%. b) After 600 °C-30 minutes annealing of the previous samples, the nanopores disappear due to the Au/residual Ag inter-diffusion. c) After a second dealloying process on the previously annealed samples, the surface nanoporous structure is, again, obtained with the porosity fraction increased to 50%.

The morphology evolution of nano-grained Ag and Au films deposited on polystyrene (PS) and poly(methyl methacrylate) (PMMA) polymeric layers were studied, using the atomic force microscopy technique, when annealed above the polymers glass transition temperature. The main effects on the morphology changes were identified with those concerning the embedding kinetics of the Ag and Au nanoparticles in the PS or PMMA layers. The embedding process of the nanoparticles follows as a consequence of the long-range mobility of the polymeric chains above the glass transition temperature. In particular, the dependence of the nanoparticles mean height and surface density on the annealing time at various temperatures was quantified. The analyses of these behaviors allowed us: (1) to distinguish the overall embedding process in a first stage in which a thin wetting layer of the polymer coats the nanoparticles followed by a true embedding process of the nanoparticles into the polymer layer; (2) to evaluate the characteristic coating time for the Ag and Au nanoparticles in the PS and PMMA in the first stage; (3) to evaluate the characteristic embedding velocity for the Ag and Au nanoparticles in the PS and PMMA in the second stage; (4) to derive the activation energies for the embedding process of the Ag and Au nanoparticles in PS and PMMA; (5) to identify the embedding statistics of the Ag and Au nanoparticles in PS and PMMA with a "failure" Weibull statistics.

The ability of tailoring surface properties is crucial in a large number of applications, so that a wide range of surface engineering techniques has been developed in the last decades. Among these techniques, those based on the surface functionalization by means of self-assembled monolayers and Langmuir–Blodgett (LB) films are peculiarly attractive because of, simplicity, versatility. In particular, this work concerns the functionalization of insulating surface with macromolecular systems disguised as LB films. In particular, we will show that patterned LB films of poly(2-vinylpyridine) (P2VP) and polystyrene (PS) blends can be obtained by careful control of the ratio of polymer components in the blend. Surface separation phase phenomena, crucial to the patterning purposes, can be evidenced by ToF-SIMS chemical imaging. Furthermore, the film morphology can be thoroughly examined by means of scanning probe microscopies (SPM) techniques. It will be shown that three main types of structures can be obtained by changing the ratio between two polymers. In particular, by increasing the relative amount of PS, structures with different shapes can be fabricated. Round-shaped structures have been obtained by using low relative quantity of PS, single wires and entangled wires have been obtained by using relative intermediate quantity of PS and high relative quantity of PS, respectively.

Ultra thin structured polymer films have been prepared by horizontal precipitation Langmuir–Blodgett (HP-LB) method of polymer blends. In particular we used mixtures of two incompatible polymers, poly-2-vinylpyridine and polystyrene, the former giving the necessary surface activity for LB film formation. Upon spreading at the air–water interface, the blend forms different surface structures depending on the relative amount of the two components. By adjusting the experimental parameters it is possible to obtain relatively regular structures in the submicron size range, which can be transferred on a solid substrate. These systems have been investigated by means of SIMS and atomic force microscopy.

Periodically twinned Si nanowires were fabricated on Si surface by high-temperature annealing, in vacuum, of deposited colloidal Au nanoparticles. While performing the annealing process in a gas carrier with trace amounts of oxygen almost-cylindrical silica nanowires are obtained thanks to the stabilizing effect of the oxygen, faceted nanowires are obtained in vacuum condition. In this last case, nanowires with diameter in the 70–150 nm range and length of some microns are obtained. They present an arrangement of periodically twinned segments with a rather uniform thickness along the entire growth length. A minimum surface energy and strain energy argument is used to explain the formation of periodic twins in the Si nanowires. The thickness of the periodic twinned segments is found to be linearly proportional to the nanowire diameter, and a constant volume model is used to explain the relation. By the fit of the experimental data, in particular, an estimation of the twin energy formation is obtained.

We report on an experimental study of the coalescence-driven grow process of colloidal Au nanoparticles on SiO 2 surface. Nanoparticles with 30, 50, 80, 100 nm nominal diameters on a SiO 2 substrate were deposited, from solutions, by the drop-casting method. Then, annealing processes, in the 573–1173 K temperature range and 900–3600 s time range, were performed. Using scanning electron microscopy analyses, the temporal evolution of the nanoparticles sizes has been studied. In particular, for all classes of nanoparticles, the experimental-obtained diameters distributions evidenced double-peak shapes (i. e. bimodal distributions): a first peak centered (and unchanged changing the annealing temperature and/or time) at the nominal diameter of the as-deposited nanoparticles, 〈 D 0 〉, and a second peak shifting at higher mean diameters, 〈 D C 〉, increasing the annealing temperature and/or time. This observation suggested us a coalescence-driven growth process of a nanoparticles sub-population. As a consequence, the temporal evolution of 〈 D C 〉 (for each class of nanoparticles and each annealing temperature), within the well-established particles coalescence theoretical framework, has been analyzed. In particular, by the analyses of the experimental data using relations as prescribed by the theoretical model, a characteristic size-dependent activation energy for the Au nanoparticles coalescence process has been evaluated.

In this review, we discuss the basic concepts related to (co-)evaporation and (co)sputtering based fabrication methods and the electrical properties of polymer-metal nanocomposite films. Within the organic-inorganic hybrid nanocomposites research framework, the field related to metal-polymer nanocomposites is attracting much interest. In fact, it is opening pathways for engineering flexible composites that exhibit advantageous electrical, optical, or mechanical properties. The metal-polymer nanocomposites research field is, now, a wide, complex, and important part of the nanotechnology revolution. So, with this review we aim, starting from the discussion of specific cases, to focus our attention on the basic microscopic mechanisms and processes and the general concepts suitable for the interpretation of material properties and structure–property correlations. The review aims, in addition, to provide a comprehensive schematization of the main technological applications currently in development worldwide.

Despite to the importance on the charge carrier injection and transport at organic/metal interface, there is yet an incomplete estimation of the various contribution to the overall dipole. This work shows how the mapping of the surface potential performed by Kelvin Probe Force Microscopy (KPFM) allows the direct observation of the interface dipole within an organic/metal multilayered structure. Moreover, we show how the sub-surface sensitivity of the KPFM depends on the thickness and surface coverage of the metallic layer. This paper proposes a way to control the surface potential of the exposed layer of an hybrid layered system by controlling the interface dipole at the organic/metal interface as a function of the nanometer scale thickness and the surface coverage of the metallic layer. We obtained a layered system constituted by repeated sequence of a copolymer film, poly(n-butylacrylate)-b-polyacrilic acid, and Au layer. We compared the results obtained by means of scanning probe microscopy technique with the results of the KPFM technique, that allows us to obtain high-contrast images of the underlying layer of copolymer behind a typical threshold, on the nanoscale, of the thickness of the metal layer. We considered the effect of the morphology of the gold layer on the covered area at different thicknesses by using the scanning electron microscopy technique. This finding represents a step forward towards the using of dynamic atomic force microscopy based characterization to explore the electrical properties of the sub-surface states of layered nanohybrid, that is a critical point for nanohybrid applications in sensors and energy storage devices.

The C 60 erosion behaviour of poly(methyl)methacrylate (PMMA), poly(α-methyl)styrene (PAMS) and polystyrene (PS) has been studied at various temperatures and compared with that under Ga + irradiation. Strong variations of erosion yields are observed, indicating that chemical degradation mechanisms are operating. In particular, our results suggest that fast depolymerization mechanisms are important in leaving the surface of the sputter crater virtually undamaged. Since such mechanisms are connected with the chemical nature of the polymer, the possibility of performing molecular depth profiling of polymers with C 60 appears to depend strongly on the chemical nature of the system under study.

When disperse in biological fluids, engineered nanoparticles are selectively coated with proteins, resulting in the formation of a protein corona. It is suggested that the protein corona is critical in regulating the conditions of entry into the cytoplasm of living cells. Recent reports describe this phenomenon as ubiquitous and independent of the nature of the particle. For nanomedicine applications however, there is a need to design advanced and cost-effective coatings that are resistant to protein adsorption and that increase the biodistribution in vivo. In this study, phosphonic acid poly(ethylene glycol) copolymers were synthesized and used to coat iron oxide particles. The copolymer composition was optimized to provide simple and scalable protocols as well as long-term stability in culture media. It is shown that polymers with multiple phosphonic acid functionalities and PEG chains outperform other types of coating, including ligands, polyelectrolytes and carboxylic acid functionalized PEG. PEGylated particles exhibit moreover exceptional low cellular uptake, of the order of 100 femtograms of iron per cell. The present approach demonstrates that the surface chemistry of engineered particles is a key parameter in the interactions with cells. It also opens up new avenues for the efficient functionalization of inorganic surfaces., 21 page, 7 figures,Biomacromolecules 2014

Semiconducting and insulating polymers and copolymers/Au nanograins based hybrid multilayers (HyMLs) were fabricated on p-Si single-crystal substrate by an iterative method that involves, respectively, Langmuir-Blodgett and spin-coating techniques (for the deposition of organic film) and sputtering technique (for the deposition of metal nanograins) to prepare Au/HyMLs/p-Si Schottky device. The electrical properties of the Au/HyMLs/p-Si Schottky device were investigated by current-voltage (I–V) measurements in the thickness range of 1-5 bilayers (BL).At different number of layers, current-voltage (I–V) measurements were performed. Results showed a rectifying behavior. Junction parameters, such as barrier height (BH), from the I–V measurements for example for the PMMA-b-PS based Au/HyMLs/p-Si structure were obtained as 0.72±0.02 eV at 1BL and 0.64±0.02eV at 5BL. It was observed that the BH value of 0.61 eV obtained for the 5 BL PS based Au/HyMLs/p-Si structure was lower than the value of 0.68 eV of conventional Au/p-Si Schottky diodes. Thus, modification of the interfacial potential barrier for Au/p-Si diodes has been achieved using a thin MLs of different polymers based HyMls semiconductor.

Patterned metallic thin films have attracted a lot of attention, in recent years, due to their wide technological applications. On the basis of this fact, in the present work, we illustrate a simple, versatile, and low-cost methodology to prepare surface micro-patterns in nanoscale deposited Au films. The methodology is based on the following steps: (a) to perform nanoscale Au film depositions assisted by micrometric templates to obtain the deposited Au film micrometric patterned in specific and desired ways (micrometric squares, hexagons, aEuro broken vertical bar), and (b) by low-temperature thermal processes (< 300 A degrees C) to induce a dewetting process of the PMMA to guide specific patterning effects in the top nanoscale Au film. In this approach, the Au surface pattern order is established by the template confined deposition on a micrometric scale while the realization and control of the Au surface pattern is given by the control of the dewetting process of the underlaying substrate, without invoking high temperature thermal processes.

Colonization of roots by arbuscular mycorrhizal (AM) fungi in several annual crops in two consecutive seasons was compared with, in the second season, the density of fungal propagules in the soil with the use of a bioassay. Root density decreased down the soil profile in both years in all crops, and a high proportion of roots were mycorrhizal throughout the profile. AM colonization decreased down the profile in cotton and lablab in the second season only. The bioassay indicated that most propagules of AM fungi in soils under cotton were located near the surface, with virtually no propagules at 1 m. The absence of propagules at depth indicates a lack of mycelium deep in the soil, and suggests that mycorrhizas are primarily initiated in the surface soil and that the fungi colonize the root system mostly through secondary spread down the profile. The use of AM colonization in the field as an indicator of propagule density and symbiotic function should be qualified by an understanding of the depth in the soil from which roots were extracted.

In an experiment to determine the influence of mycorrhizal colonization on root development, fertilized seedlings of cotton were grown in long tubular pots. Inoculation of soil with an isolate of Glomus mosseae at 10, 25 or 40 cm below the soil surface resulted in spread of arbuscular mycorrhizas up and down the root system, and localized elongation of roots following colonization. Specific root length was not influenced by colonization. Increases in local root density at the point of inoculation were observed, though total root mass in relation to shoot mass declined following initiation of mycorrhizas.

Insulating, polymethylmethacrylate (PMMA), and semiconducting, poly(3-hexylthiophene) (P3HT), nanometer thick polymers/Au nanoparticles based hybrid multilayers (HyMLs) were fabricated on p-Si single-crystal substrate. An iterative method, which involves, respectively, spin-coating (PMMA and P3HT deposition) and sputtering (Au nanoparticles deposition) techniques to prepare Au/HyMLs/p-Si Schottky device, was used. The barrier height and the ideality factor of the Au/HyMLs/p-Si Schottky devices were investigated by current-voltage measurements in the thickness range of 1-5 bilayers. It was observed that the barrier height of such hybrid layered systems can be tuned as a function of bilayers number and its evolution was quantified and analyzed. © 2013 AIP Publishing LLC.

Two methodologies to build new nanostructured hybrid layered nanocomposites are presented. The first one involves the preparation of hybrid metal/polymer nanolayers (NLs) by combining two monolayer preparation techniques: Horizontal Precipitation Langmuir Blodgett method (HP-ML), for copolymer monolayers and sputter deposition technique, for Au NLs deposition. The second methodology is aimed to prepare regular arrays of nanopores, with diameter ranging between 40-100 nm, in ultra-thin films of electroactive polymers, to obtain embedded regular arrays of nanopores filled by a further electroactive organic component. The produced hybrid MLs have been characterized by means of X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and Grazing Incidence X-ray Diffraction (GI-XRD). In the first case, current-voltage (I-V) measurements demonstrate that the multilayers exhibit a bipolar conduction behaviour (electrons and holes carriers), with a peculiar transition in the nature of the majority carriers (from holes to electrons) above a threshold number of bilayers. In the second case, it is found that the degree of pore filling, as well as the polymer crystallinity can be easily modulated, prompting the tuning of the photoresponse of the nanocomposites.

In this work, we propose a new approach to prepare surface micro-patterns in nanoscale deposited Au films. In particular, we exploit the idea to use a template confined dewetting aging not directly on the deposited Au film but on an underlying poly(methylmethacrylate) (PMMA) substrate by thermal processes. The idea consists of the following basic concepts: (a) to perform nanoscale Au film deposition assisted by micrometric templates to obtain a template confined film and (b) by low-temperature thermal processes (

We report on the use of the self-organization process of sputtered gold nanoparticles on a self-assembled block copolymer film deposited by horizontal precipitation Langmuir-Blodgett (HP-LB) method. The morphology and the phase-separation of a film of poly-n-butylacrylate-block-polyacrylic acid (Pn BuA-b-PAA) were studied at the nanometric scale by using atomic force microscopy (AFM) and Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The templating capability of the Pn BuA-b-PAA phase-separated film was studied by sputtering gold nanoparticles (NPs), forming a film of nanometric thickness. The effect of the polymer chain mobility onto the organization of gold nanoparticle layer was assessed by heating the obtained hybrid Pn BuA-b-PAA/Au NPs bilayer at T >Tg. The nanoparticles' distribution onto the different copolymer domains was found strongly affected by the annealing treatment, showing a peculiar memory effect, which modifies the AFM phase response of the Au NPs layer onto the polar domains, without affecting their surfacial composition. The effect is discussed in terms of the peculiar morphological features induced by enhanced mobility of polymer chains on the Au NPs layer.

This paper reports on the synthesis and surface immobilization of a 40-membered chiral salen macrocycle via a surface reaction between its hydroxyl-terminated branches and a carboxy-functionalized platform using N,N′-dicyclohexylcarbodiimide (DCC) as activating molecule of the carboxylic group of 11-mercaptoundecanoic acid, SAM. The peculiarity of this surface reaction at the carboxy-terminated platform is that a multiple site esterification is obtained, as indicated by time-of-flight secondary ion mass spectrometry measurements. Copyright © 2010 John Wiley & Sons, Ltd.

The growth of a room-temperature sputter-deposited thin Au film on two soft polymeric substrates, polystyrene (PS) and poly(methyl methacrylate) (PMMA), from nucleation to formation of a continuous film is investigated by means of atomic force microscopy. In particular, we studied the surface morphology evolution of the film as a function of the deposition time observing an initial Au three-dimensional island-type growth. Then the Au film morphology evolves, with increasing deposition time, from hemispherical islands to partially coalesced worm-like island structures, to percolation, and finally to a continuous and rough film. The overall Au morphology evolution is discussed in the framework of the interrupted coalescence model, allowing us to evaluate the island critical radius for the partial coalescence R c=8.7±0.9 nm for Au on PS and R c=7.6±0.8 nm for Au on PMMA. Furthermore, the application of the kinetic freezing model allows us to evaluate the room-temperature surface diffusion coefficient D s≈1.8×10−18 m2/s for Au on PS and D s≈1.1×10−18 m2/s for Au on PMMA. The application of the Vincent model allows us, also, to evaluate the critical coverage (at which the percolation occurs) P c=61% for Au on PS and P c=56% for Au on PMMA. Finally, the dynamic scaling theory of a growing interface was applied to characterize the kinetic roughening of the Au film on both PMMA and PS. Such analyses allow us to evaluate the dynamic scaling, growth, and roughness exponents z=3.8±0.4, β=0.28±0.03, α=1.06±0.05 for the growth of Au on PS and z=4.3±0.3, β=0.23±0.03, α=1.03±0.05 for the growth of Au on PMMA, in agreement with a non-equilibrium but conservative and linear growth process in which the surface diffusion phenomenon plays a key role.

The study of surface morphology of Au deposited on mica is crucial for the fabrication of flat Au films for applications in biological, electronic, and optical devices. The understanding of the growth mechanisms of Au on mica allows to tune the process parameters to obtain ultra-flat film as suitable platform for anchoring self-assembling monolayers, molecules, nanotubes, and nanoparticles. Furthermore, atomically flat Au substrates are ideal for imaging adsorbate layers using scanning probe microscopy techniques. The control of these mechanisms is a prerequisite for control of the film nano- and micro-structure to obtain materials with desired morphological properties. We report on an atomic force microscopy (AFM) study of the morphology evolution of Au film deposited on mica by room-temperature sputtering as a function of subsequent annealing processes. Starting from an Au continuous film on the mica substrate, the AFM technique allowed us to observe nucleation and growth of Au clusters when annealing process is performed in the 573-773 K temperature range and 900-3600 s time range. The evolution of the clusters size was quantified allowing us to evaluate the growth exponent 〈z〉 = 1.88 ± 0.06. Furthermore, we observed that the late stage of cluster growth is accompanied by the formation of circular depletion zones around the largest clusters. From the quantification of the evolution of the size of these zones, the Au surface diffusion coefficient was evaluated in D ( T ) = [ ( 7 . 42 × 1 0 − 13 ) ± ( 5 . 94 × 1 0 − 14 ) m 2 /s ] exp ( − ( 0.33 ± 0.04 ) eV k T ) . These quantitative data and their correlation with existing theoretical models elucidate the kinetic growth mechanisms of the sputtered Au on mica. As a consequence we acquired a methodology to control the morphological characteristics of the Au film simply controlling the annealing temperature and time.

ToF-SIMS images were obtained from a section of a tooth, obturated by means of a new calcium-silicate based cement (wTCF) after storage for 1 month in a saline solutions (DPBS), in order to simulate the body fluid effects on the obturation. Afterwards, ToF-SIMS spectra were obtained from model samples, prepared by using the same cement paste, after storage for 1 month and 8 months in two different saline solutions (DPBS and HBSS). ToF-SIMS spectra were also obtained from fluorine-free cement (wTC) samples after storage in HBSS for 1 month and 8 months and used for comparison. It was found that the composition of both the saline solution and the cement influenced the composition of the surface of disks and that longer is the storage greater are the differences. Segregation phenomena occur both on the cement obturation of the tooth and on the surface of the disks prepared by using the same cement. Indirect evidences of formation of new crystalline phases are supplied.

Au nanostructured film was deposited on mica by room temperature RF sputtering. The growth mechanism of the film was studied analyzing the evolution of the film morphology as a function of its thickness by the atomic force microscopy. In the early stages of a growth the film evolution proceeds by the nucleation and growth of nanoclusters. After a critical thickness the growth of microclusters formed by the joining of nanoclusters in preferential nucleation sites, onto a quasicontinuous film, is observed. We quantified the evolution of the mean nanoclusters height and surface density and of the film roughness. This data were analyzed by the dynamic scaling theory of growing interfaces obtaining the scaling and roughness exponents z and β whose values suggest a conservative growth process. We also quantified the growth of the microclusters showing that it is consistent with a coalescence/impingement dynamic. About the formation of the microclusters, furthermore, we speculate that their origin is strongly correlated to the features of the sputtering technique in connection with the deposition on a high-diffusivity substrate.

A self assembling method based on osmotic procedure allowed fabricating nanostructured aggregates of dinuclear complexes made of Zn-porphyrin bridges between Pt(II) acetylide tethers. The choice of experimental parameters, such as solvent/non solvent couple and temperature allows achieving nanostructures that look like rod-like crystals and spheres, the latter ones showing either solid or concave internal structures. The porphyrin bridged di-bis(triphenylphosphine)platinum phenylacetylide, porphyrin bridged di-bis(triphenylphosphine)platinum p-nitrophenylacetylide and porphyrin bridged di-bis(triphenylphosphine)platinum p-methoxyphenylacetylide, were synthesized by the coupling of 2,8,12,18-tetraethyl-5,15-diethynyl-3,7,13,17-tetramethylporphyrinatozinc(II) with the corresponding trans-[Pt(PPh3)2(C≡C-R)Cl] complexes (R = C6H5, C6H4NO2, C6H4OCH3). The molecular structures were assessed with NMR and ToF-SIMS studies and the nanostructure formation was revealed with SEM investigations. The results could be of interest for future applications in optoelectronic devices, sensors, biotechnology and light harvesting. © 2008 Elsevier B.V. All rights reserved.

We report about a simple, versatile, low-cost and high-throughput methodology for the size-selected growth of SiO2 nanowires (NWs) on surfaces and on their surface decoration by Au nanoparticles (NPs). In contrast to a standard method involving the solid state reaction of thin Au films on Si at high temperature in the presence of trace amount oxygen (resulting in the formation of SiO2 NWs with a very high dispersion in diameters), the proposed method involves the same reaction between size-selected colloidal Au NPs and the Si substrate. By microscopic analyses we demonstrate that, by such a method: 1) NWs of very low diameter can be grown with respect to those originating by films; 2) the size dispersion of the obtained NWs is much lower with respect to those originating by films; 3) the NWs' diameter can be finely tuned by controlling the colloidal NPs starting size; 4) it is possible to decorate such NWs by Au NPs simply coating them by Au film and inducing, by a thermal process, the dewetting of the film.

The Authors describe the evolution of their anesthesiological techniques in the surgical repair of inguinal hernia. In this study they compare indications, complications, costs, hospital stay, length of surgery, postoperative pain and return to work after operations performed under local, spinal and general anesthesia. In their experience inguinal hernia treatment with local anesthesia and a tension-free technique is the preferred method of surgical repair.

The Authors, after a short review of the literature, report their clinical experience using alpha-cyanoacrylate, a new tissue adhesive. This substance shows haemostatic and adhesive properties and it is useful to protect surgical wounds. On these bases, the alpha-cyanoacrylate shows definite directions in oral and maxillo-facial surgery.

The Authors describe 5 cases of Bochdalek's posterolateral diaphragmatic hernia in terms of their clinical, diagnostic, and therapeutic aspects. They also explain their criteria in the choice of surgical approaches and describe reconstruction methods used in the repair of large hernias. Finally, they propose a special schedule of postoperative management to be used in connection with neonatal surgery, where surgical mortality is still high.

The authors report a case they had the opportunity to observe, surgically treated (thoraco-phrenotomy, removal of the herniated mass, repair of the diaphragmatic breach). They illustrate the genesis of such abnormality, its incidence and symptomatology. The Authors, moreover, dwell upon the diagnostic problems caused by Bochdalek's hernia with retroperitoneal contents, and upon the advantages shown by the thoracic way of aggression in the light of their own experience.

Starting from a consecutive series of 53 bronchographies performed under local anesthesia, in subjects with carcinoma of the lung ascertained by operation, the Authors analyse both the bronchographical aspects which most frequently come under the surgeon's observation, and the usefulness of this investigation in formulating the operating plan. As regards carcinomas of the large and medium bronchi, the bronchographic aspects they found most frequently are occlusion (82%) both in the form of sudden arrest and in the form of a cone image and stenosis (18%). In peripheral carcinomas, on the other hand, most characteristic bronchographic signs are identified as occlusion (58%) (amputation and stenosis) and dislocation (38%) with rigidity of one or more small calibre bronchi (rigid impairment). On the basis of their experience the Authors conclude that bronchography constitutes an almost indispensable examination for diagnostic purposes in malignant neoplasias, especially in the initial stage, when located outside the field of action of bronchoscopy, and can supply elements indispensable in the preoperative operatability judgement. In fact it not only gives very reliable information on the anatomical situation of the bronchus, as well as on the site and presumed starting-point of the neoplasia, but also supplies more approximate elements with regard to the extent of the neoplasia and any presence of lymphoglandular metastases.

After a brief recall of the main problems of post-colostomy patients, the authors describe the method of colonic irrigation, which affords the complete discharge of fecal matter and continence over the ensuing 24 hours. The authors give an account of the results obtained with this methodology at the Stoma Center of Catania; and they conclude that the method in question, applied correctly and appropriate cases, seems to represent the treatment of first choice for the postoperative management of colostomy cases.