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Polypyrrole (PPy)-based nanocomposites are synthesized by a micro-emulsion oxidative chemical polymerization of pyrrole monomer. Graphene platelets (GP), extracted from Shungite mineral powders through innovative procedures, are used as nanoinclusions to enhance the interesting properties of the pure polymer. SEM and HR-TEM analyses evidence that diverse PPy nanostructures are obtained in the presence of different dopant surfactants: globular grains with sodium dodecyl sulfate (SDS) anionic surfactant, and tubular features with hexadecyltrimethylammonium bromide (CTAB) cationic surfactant. Raman spectroscopy reveals that the polymer chains are in a semi-oxidized state. Functional characterizations evidence that the PPy-based nanocomposites doped with SDS are characterized by improved charge transport properties. (C) 2019 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of AEM2017.

The synthesis of CdSe quantum dots (QDs) from a single source precursor is a known way to form a nanocomposite by its thermal decomposition. Recently, some of them have been used to grow QDs by direct laser patterning. Here, the authors report the study of the formation of the CdSe QDs starting from the decomposition of the 2-(N,N-dimethylamino)ethylselenolate of cadmium dispersed in a polymethylmethacrylate film induced both by heating and laser patterning. The formation of the CdSe QDs under annealing at 150 °C is studied as a function of the precursor concentration and molar ratio with respect to two different QD ligands such as oleic acid and oleylamine. The photoluminescent spectra of the formed nanocomposite show that the oleic acid induces the formation of the direct bandgap, while oleylamine shows only a broadband emission. The laser patterning of the film was carried out with a UV laser (355 nm) with a pulse frequency of 40 kHz and a fluence of 1.06 J/cm2. The resulting patterned areas were characterized by a fluorescence microscope showing the formation of a photoluminescence path only when the ligands were present, suggesting the formation of the functional (photoluminescent) QDs.The synthesis of CdSe quantum dots (QDs) from a single source precursor is a known way to form a nanocomposite by its thermal decomposition. Recently, some of them have been used to grow QDs by direct laser patterning. Here, the authors report the study of the formation of the CdSe QDs starting from the decomposition of the 2-(N,N-dimethylamino)ethylselenolate of cadmium dispersed in a polymethylmethacrylate film induced both by heating and laser patterning. The formation of the CdSe QDs under annealing at 150 °C is studied as a function of the precursor concentration and molar ratio with respect to two different QD ligands such as oleic acid and oleylamine. The photoluminescent spectra of the formed nanocomposite show that the oleic acid induces the formation of the direct bandgap, while oleylamine shows only a broadband emission. The laser patterning of the film was carried out with a UV laser (355 nm) with a pulse frequency of 40 kHz and a fluence of 1.06 J/cm2. The resulting patterned areas were chara...

This study is devoted to synthesizing and modifying conductive Ti-doped diamond (TiD) biosubstrates with polyaniline (PANI) to provide a soft interface with high ionic conductivity and charge storage capacity for developing advanced scaffolds and implantable electrode materials. The diamond supports are prepared by an ad-hoc chemical vapor deposition methodology allowing for the synthesis and contemporary doping of diamond lattice. An optimized potentiostatic electropolymerization method assures the growth of a homogenous PANI coating on a diamond surface. Scanning electron microscopy, atomic force microscopy, Raman, and reflectance infrared spectroscopy characterizations guarantee the production of nanostructured diamond layers with high surface electrical conductivity and good phase quality as well as of a rough polymer film in the conductive emeraldine form. Cyclic voltammetry and electrochemical impedance spectroscopy measurements point out a quasi-reversible electron transfer among polymer chains ruled by the bulky dodecyl sulfate anion chosen as polymer dopant. This induces a cation exchange with the solution upon backbone redox reactions. The capability of the PANI-TiD system to transduce ionic current into electronic current and vice versa via redox reaction with the surroundings can be reliably exploited to reproduce electrical stimulation processes through which to mimic the original bioelectricity functions of the human body for advanced biomedical applications.

The Poster is realised within the Research Night 2019 (September 27 2019 Frascati) Nanotechnologies and photonics are a new field of research that is gradually becoming part of our daily life even though we are not always aware of them. In the presentation to the public we want to show in a simple and intuitive way these two concepts and how they decline in everyday reality. &nbsp

This work details the synthesis and characterizations of PVA-graphene platelets and PANI-nanodiamonds nanocomposites as suitable materials to be used as inks for additive manufacturing processes by 3D methodology. The PVA-based nanocomposites are generated by an optimized synthetic route, in which the chemical crosslinking of PVA with maleic anhydride is realized in the presence of dispersed graphene platelets. The PANI-based nanocomposites are obtained starting from aniline monomer by an “in situ” polymerization process carried out in a dispersion of purified nanodiamonds. The 3D layer-by-layer printing of polymer-based nanocomposites colloidal dispersion allows to produce well-shaped solid objects that are promising as scaffolds for biomedical applications.This work details the synthesis and characterizations of PVA-graphene platelets and PANI-nanodiamonds nanocomposites as suitable materials to be used as inks for additive manufacturing processes by 3D methodology. The PVA-based nanocomposites are generated by an optimized synthetic route, in which the chemical crosslinking of PVA with maleic anhydride is realized in the presence of dispersed graphene platelets. The PANI-based nanocomposites are obtained starting from aniline monomer by an “in situ” polymerization process carried out in a dispersion of purified nanodiamonds. The 3D layer-by-layer printing of polymer-based nanocomposites colloidal dispersion allows to produce well-shaped solid objects that are promising as scaffolds for biomedical applications.

This study is focused on the surface engineering of detonation nanodiamonds (DND) for the delivering of therapeutic agents, and on the developing of strategies for the DND conjugation with biologically active substances. Oxidized and differently amino-functionalized DND have been investigated to identify their chemical and structural features. A series of complexes have been produced by reacting the activated DND particles with four antioxidant molecules abundant in grapes and wine: resveratrol (R), rutin hydrate (U), epicatechin (E) and chlorogenic acid (C). Drug up-take is found strictly dependent on the affinity between molecules and selectively modified DND surfaces. All adducts, prepared avoiding potentially toxic solvents, reached a concentration suitable for therapeutic applications. MTT assay, performed on SH-SY5Y neuroblastoma cell line, evidenced that the conjugation with DND amplifies the bioactivity of the metabolites with respect to the relative pure molecules. However, depending on the DND surface chemistry, the various metabolites are found to exert markedly different effects on tumor cell viability, producing increase or decrease of proliferation. These findings indicate that a tailoring of the DND surface chemistry, specific for each molecule, is required not only to improve binding/delivering of active substances to biological targets, but also to achieve the desired therapeutic results.

This study explores the feasibility to use electroconductive Ti-doped polycrystalline diamond layers as scaffolds for tissue engineering. The synthesis of the diamond-based materials is accomplished in a HFCVD reactor where Ti(IV) acetyl acetonate powders are delivered by N2 fluxes to the growing diamond phase. In-depth investigations (Raman spectroscopy, SEM, AFM, XRD, XPS) allowed the characterization of the morphological/structural/compositional features and the properties of charge transport (KPFM, I-V) induced in the diamond layers by the incorporation of Ti-species. The bioactivity of the Ti-doped diamond surface was verified investigating the growth of MG-63 osteoblast-like cells by using MTT assays and confocal microscopy. The study evidenced a net increase of cell replication rate on diamond scaffolds after 4 days of incubation. After 6-days incubation, the cell growth on the Ti-doped diamond scaffolds increased up to 150% compared with the reference polystyrene tissue culture vessel, with a dominant presence of cells in active division. The cell behavior is discussed and related to the structural and functional surface properties of the Ti-diamond systems, acting as bioactive platforms able to offer an extremely beneficial environment for cell proliferation and viability. © 2020 Elsevier B.V.

The superconducting properties of YBa2Cu3O7-δ (YBCO) film can be significantly improved through the introduction of nanosized defects. In this work, the Chemical Solution Deposition (CSD) of YBCO film doped with Nanodiamond (ND) is proposed. ND introduction in YBCO (YBCO-ND) has never been reported until our recent preliminary study [1] that showed ND potential for the improvement of YBCO transport properties. Further optimizations of the YBCO-ND CSD process have been accomplished and results are illustrated in the present paper. Good epitaxial films have been obtained and a significant improvement of film morphology and superconducting properties has been observed with respect to pure YBCO. Dopant seems to have a beneficial effect on YBCO morphology. In fact, YBCO-ND films generally show denser, smoother and more connected surfaces. The good morphology corresponds to increased superconducting properties. Higher zero-field critical current densities have been measured in the temperature range from 10 K to 77 K (i.e. 18 and 13 ± 1.2 MA•cm−2 respectively for YBCO-ND and pure YBCO at 10 K). These results could be mainly ascribed to an improvement of the percolation path due to the increase of film density and grain coalescence. It might be supposed that ND influences the nucleation mechanisms of YBCO films facilitating c-axis orientation, but the actual role sill needs to be clarified.

The paper reports on the feasibility of obtaining graphene nanomaterials with remarkable structural and chemical features from shungite rocks. The investigation of the composition and structural modifications induced in the pristine, natural C-containing mineraloid by a specifically designed physicochemical purification treatment is performed by a combined use of several techniques (scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopies). The adopted material processing enables efficient extraction of the C phase in the form of thin polycrystalline platelets of a few hundred nanometers sizes, and formed by 6-10 graphene sheets. About 80% of such nanostructures are characterized by a regular sp2 C honeycomb lattice and an ordered stacking of graphene layers with a d-spacing of ∼0.34 nm. The low oxygen content (∼5%), mainly found in the form of hydroxyl functional groups, provides the graphene platelets (GP) with a chemistry strictly close to that of conventional rGO materials. Such a feature is supported by the high conductivity value of 1.041 × 103 S cm-1 found for pelletized GP, which can be considered a valuable active material for a wide spectrum of advanced applications.

We report here on soft-template electropolymerizations of polypyrrole (Ppy)-based nanocomposites triggered by graphene platelets (GP) from shungite (SH) rocks. A properly designed procedure for an efficient extraction of graphene platelets from SH powders is established to produce remarkable graphene materials in a low oxidation state and with a high electrical conductivity (1490 S cm−1). By using positively and negatively charged templating surfactants the role played by the graphene units on the electropolymerization reactions is pointed out by SEM, EDX, TEM, SAED, XPS and Raman spectroscopy. The morphological/structural characterizations highlight that GP from SH have a surface chemistry suitable for selective and mutual interactions with the growing Ppy chains. CV and galvanostatic charge/discharge measurements evidence that GP improve the transport of both electrons and ions within the bulk material by means of a synergistic action with the polymer phase. This cooperative behavior induces an enhancement of the specific capacitance up to 250 F g−1 at 2 A g−1. The Ppy-GP materials produced following the settled protocols result to be appropriate for fabricating multifunctional charge transport and storage electroactive systems.

A surface nanosculpturing is performed on twill wave carbon fibers patches by means of hydrogen plasma treatments in a dual-mode MW-RF CVD reactor. A tufts-like texture is realized on the surface of the single fibers of the patches that show an enhanced electrochemical reactivity and capacitive behavior with respect to the pristine material. The nanostructured carbon fiber fabrics are successfully used as support for the electrochemical growth of nickel species nanoflakes. The hybrid NiOx(OH)y-carbon fibers electrodes exhibit remarkable increases of both capacitive and pseudo-capacitive currents up to specific capacitance values of 1050 F g −1 . Charge storage capability given by the coupling of Ni-species and etched carbon fibers is preserved after long time cycling and is also maintained after mechanical deformation, making such composite systems promising as suitable electrode materials for flexible energy storage devices.

A hybrid chemical vapor deposition (CVD)-powder flowing technique specifically developed in lab has been employed to produce high-quality polycrystalline diamond layers containing Ti inclusions. Morphology, structural features, and surface composition of nanocomposite diamond-based samples produced by different growth times have been analyzed by scanning electron microscopy, Raman and Auger spectroscopy, respectively. The CVD methodology adopted for the Ti incorporation in the diamond lattice does not perturb the crystalline quality of the diamond matrix, therefore maintaining the outstanding properties of the C-sp3 phase. The functional properties of the nanocomposite layers have been tested by nanoindentation and I–V measurements. The electrochemical performance of the diamond/Ti electrodes is evaluated by performing cyclic voltammetry in different media, namely, acidic, neutral, and basic aqueous solutions, and by estimating the rate constant of heterogeneous electron transfer to diamond surface for the ferro/ferricyanide redox couple. The rather good electrochemical performances, the mechanical strength, and the chemical inertness of the Ti-doped diamond electrodes produced by the CVD approach, comply with the whole set of technological requirements, such as robustness, long durability, and biocompatibility, required for use in hostile environments or in biological systems.