Monitoring of Carbonated Hydroxyapatite Growth on Modified Polycrystalline CVD-Diamond Coatings on Titanium Substrates

Production of diamond coatings on titanium substrates has demonstrated as a promising strategy for applications ranging from biosensing to hard tissue engineering. The present study focuses on monitoring the nucleation and growth of bone-like carbonated-hydroxyapatite (C-HA) on polycrystalline diamond (PCD) synthetized on titanium substrate by means of a hot filament chemical vapor deposition (HF-CVD) method. The surface terminations of diamond coatings were selectively modified by oxidative treatments. The process of the C-HA deposition, accomplished by precipitation from simulated body fluid (SBF), was monitored from 3 to 20 days by Raman spectroscopy analysis. The coupling of morphological and structural investigations suggests that the modulation of the PCD surface chemistry enhances the bioactivity of the produced materials, allowing for the formation of continuous C-HA coatings with needle-like texture and chemical composition typical of those of the bone mineral. Specifically, after 20 days of immersion in SBF the calculated carbonate weight percent and the Ca/P ratio are 5.5% and 2.1, respectively. Based on these results, this study brings a novelty in tailoring the CVD-diamond properties for advanced biomedical and technological applications

Self-standing 3D-printed PEGDA–PANIs electroconductive hydrogel composites for pH monitoring

Additive manufacturing (AM), or 3D printing processes, is introducing new possibilities in electronic, biomedical, sensor-designing, and wearable technologies. In this context, the present work focuses on the development of flexible 3D-printed polyethylene glycol diacrylate (PEGDA)- sulfonated polyaniline (PANIs) electrically conductive hydrogels (ECHs) for pH-monitoring applications. PEGDA platforms are 3D printed by a stereolithography (SLA) approach. Here, we report the successful realization of PEGDA–PANIs electroconductive hydrogel (ECH) composites produced by an in situ chemical oxidative co-polymerization of aniline (ANI) and aniline 2-sulfonic acid (ANIs) monomers at a 1:1 equimolar ratio in acidic medium. The morphological and functional properties of PEGDA–PANIs are compared to those of PEGDA–PANI composites by coupling SEM, swelling degree, I–V, and electro–chemo–mechanical analyses. The differences are discussed as a function of morphological, structural, and charge transfer/transport properties of the respective PANIs and PANI filler. Our investigation showed that the electrochemical activity of PANIs allows for the exploitation of the PEGDA–PANIs composite as an electrode material for pH monitoring in a linear range compatible with that of most biofluids. This feature, combined with the superior electromechanical behavior, swelling capacity, and water retention properties, makes PEGDA–PANIs hydrogel a promising active material for developing advanced biomedical, soft tissue, and biocompatible electronic applications

Exploiting the Properties of Ti-Doped CVD-Grown Diamonds for the Assembling of Electrodes

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

Nanodiamond-mediated crystallization in fibers of PANI nanocomposites produced by template-free polymerization : conductive and thermal properties of the fibrillar networks

The detonation nanodiamond is a novel versatile nanomaterial with tunable properties and surface chemistry. In this work, we report on a template-free method to synthesize polyaniline based nanocomposite fibers during a chemical oxidative precipitation polymerization where the cooperative interactions between nanodiamond and polyaniline nucleates trigger the final morphology of the nanocomposite. FE–SEM and TEM observations evidence the prominent growth of fibril-like structures assembled in 2-D networks of tightly woven, partially oriented fibers. Optical and Raman spectroscopy and X-ray diffraction analyses reveal that the polymer chains are in a protonated emeraldine form and organize themselves in a highly ordered 3-D spatial arrangement. Conductivity measurements performed on isolated fibers by a conductive tip of an AFM apparatus highlight that the diamond filler does not affect the conductive properties of the polyaniline matrix while increases the thermal stability of the polymer as confirmed by TGA studies

Effect of Volatile Organic Compounds Adsorption on 3D-Printed {PEGDA}:{PEDOT} for Long-Term Monitoring Devices

We report on the preparation and stereolithographic 3D printing of a resin based on the composite between a poly(ethylene glycol) diacrylate (PEGDA) host matrix and a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) filler, and the related cumulative volatile organic compounds' (VOCs) adsorbent properties. The control of all the steps for resin preparation and printing through morphological (SEM), structural (Raman spectroscopy) and functional (I/V measurements) characterizations allowed us to obtain conductive 3D objects of complex and reproducible geometry. These systems can interact with chemical vapors in the long term by providing a consistent and detectable variation of their structural and conductive characteristics. The materials and the manufacture protocol here reported thus propose an innovative and versatile technology for VOCs monitoring systems based on cumulative adsorption effects

Nanocompositi a base di polimeri conduttori e nanotubi di carbonio: preparazione, caratterizzazione e applicazioni

Il lavoro di ricerca si è focalizzato sulla preparazione e caratterizzazione di materiali nanocompositi a matrice polimerica, dove il componente nanostrutturato è costituito da nanotubi di carbonio e la matrice polimerica è data da polimeri organici conduttori. Viene detto nanocomposito un materiale costituito da due o più fasi in cui uno dei componenti presenta almeno una dimensione che è al di sotto dei 100 nm. L’importanza tecnologica di un sistema di questo tipo risiede nel fatto che l’elevata area interfacciale che si viene a produrre nel bulk del materiale può contribuire a trasformare le proprietà chimiche, morfologiche e funzionali del materiale ospite di base con bassi livelli di caricamento dell’additivo. I nanotubi di carbonio sono oggetto di grande interesse nei differenti campi della scienza e dell’ ingegneria in quanto manifestano tipiche proprietà strutturali, chimiche e fisiche che ne fanno uno dei materiali più idonei alla produzione di dispositivi tecnologici d’avanguardia. La loro integrazione in strutture composite, permette di sfruttare le loro eccezionali proprietà per la creazione di sistemi complessi dalle molteplici caratteristiche funzionali. I polimeri conduttori sono materiali organici che presentano una conduttività elettrica intrinseca a temperatura ambiente dovuta all’ esteso sistema di elettroni π che si estende su tutta la catena polimerica principale. Sono materiali che combinano l’alta conduttività normalmente riservata ai metalli con le proprietà meccaniche dei polimeri, come la flessibilità e la possibilità di fabbricarli in forma di film sottili. I materiali preparati nel corso del lavoro sperimentale sono stati sottoposti a diverse caratterizzazioni morfologiche (mediante microscopia elettronica, microscopia a forza atomica e microscopia ad effetto tunnel), strutturali (mediante spettroscopia Raman e di risonanza elettronica di spin) ed elettrochimiche. Infine sono state eseguite delle caratterizzazioni funzionali allo scopo di valutare la possibilità di integrazione dei materiali preparati in dispositivi di interesse tecnologico. Sono state condotte misure di trasporto di carica elettrica, misure piezoresistive, di foto-corrente e di conduttività elettrica in frequenza. Tali studi hanno rivelato come i materiali preparati possano avere interessanti applicazioni in dispositivi elettromeccanici e fotovoltaici di nuova generazioni e come materiali assorbitori radar e schermanti di impulsi elettromagneticiThe research work has been focalized on the preparation and characterization of Polymer Nanocomposites, in which the nanostructured component is constituted of Carbon Nanotubes whereas the polymer matrix is made of Organic Conducting Polymers. The term Nanocomposite indicates a material constituted by the combination of two or more different materials, one of which shows at least a dimension below 100 nm. The technological importance of this kind of material consists in the very high interfacial area produced in the bulk of the composite by the introduction of the nanostructured system. In fact this higher interfacial area could totally change the chemical, morphological and functional properties of the host matrix also with low loadings of additive. Carbon nanotubes are object of intensive studies between scientists and engineers because of their unique structural, chemical and physical characteristics which make them one of the most interesting materials for the production of innovative devices. Moreover their integration into composite structures allows to exploit their exceptional properties for the realization of more complex systems which can have various functionalities. Conducting Polymers (CPs) are organic conjugated polymers which show an intrinsic electrical conductivity at room temperature. This conductivity is due to the  electrons systems delocalized on the principal polymer chain. CPs are very interesting materials which combine the high conductivity typical of the metals with the mechanical properties of the polymers, such as the flexibility and the possibility to be produced as thin films. All the materials prepared during the experimental work have been subjected to several morphological characterizations (such as Scanning Electron Microscopy, Transmission Electron Microscopy, Atomic Force Microscopy and Scanning Tunnelling Microscopy), structural characterizations (such as Raman spectroscopy and Electron Spin Resonance spectroscopy) and electrochemical characterizations (such as Chronoamperometry and Ciclic Voltammetry). Finally, functional characterizations have been performed with the aim to check the possibility to integrate the prepared materials into technological devices. The functional characterizations which have been tested include charge transport measurements, piezo-resistive measurements, photo-current measurements and microwave conductivity measurements. The thesis work demonstrates as the nanocomposites based on Carbon Nanotubes and Conducting Polymers can have useful and interesting applications in electro-mechanical and photovoltaic devices and as radar absorbent and electromagnetic shielding materials when all the steps regarding the composite realization (from synthesis to characterization) are controlled and reproducible

Nanocompositi a base di polimeri conduttori e nanotubi di carbonio: preparazione, caratterizzazione e applicazioni

Il lavoro di ricerca si è focalizzato sulla preparazione e caratterizzazione di materiali nanocompositi a matrice polimerica, dove il componente nanostrutturato è costituito da nanotubi di carbonio e la matrice polimerica è data da polimeri organici conduttori. Viene detto nanocomposito un materiale costituito da due o più fasi in cui uno dei componenti presenta almeno una dimensione che è al di sotto dei 100 nm. L’importanza tecnologica di un sistema di questo tipo risiede nel fatto che l’elevata area interfacciale che si viene a produrre nel bulk del materiale può contribuire a trasformare le proprietà chimiche, morfologiche e funzionali del materiale ospite di base con bassi livelli di caricamento dell’additivo. I nanotubi di carbonio sono oggetto di grande interesse nei differenti campi della scienza e dell’ ingegneria in quanto manifestano tipiche proprietà strutturali, chimiche e fisiche che ne fanno uno dei materiali più idonei alla produzione di dispositivi tecnologici d’avanguardia. La loro integrazione in strutture composite, permette di sfruttare le loro eccezionali proprietà per la creazione di sistemi complessi dalle molteplici caratteristiche funzionali. I polimeri conduttori sono materiali organici che presentano una conduttività elettrica intrinseca a temperatura ambiente dovuta all’ esteso sistema di elettroni π che si estende su tutta la catena polimerica principale. Sono materiali che combinano l’alta conduttività normalmente riservata ai metalli con le proprietà meccaniche dei polimeri, come la flessibilità e la possibilità di fabbricarli in forma di film sottili. I materiali preparati nel corso del lavoro sperimentale sono stati sottoposti a diverse caratterizzazioni morfologiche (mediante microscopia elettronica, microscopia a forza atomica e microscopia ad effetto tunnel), strutturali (mediante spettroscopia Raman e di risonanza elettronica di spin) ed elettrochimiche. Infine sono state eseguite delle caratterizzazioni funzionali allo scopo di valutare la possibilità di integrazione dei materiali preparati in dispositivi di interesse tecnologico. Sono state condotte misure di trasporto di carica elettrica, misure piezoresistive, di foto-corrente e di conduttività elettrica in frequenza. Tali studi hanno rivelato come i materiali preparati possano avere interessanti applicazioni in dispositivi elettromeccanici e fotovoltaici di nuova generazioni e come materiali assorbitori radar e schermanti di impulsi elettromagneticiThe research work has been focalized on the preparation and characterization of Polymer Nanocomposites, in which the nanostructured component is constituted of Carbon Nanotubes whereas the polymer matrix is made of Organic Conducting Polymers. The term Nanocomposite indicates a material constituted by the combination of two or more different materials, one of which shows at least a dimension below 100 nm. The technological importance of this kind of material consists in the very high interfacial area produced in the bulk of the composite by the introduction of the nanostructured system. In fact this higher interfacial area could totally change the chemical, morphological and functional properties of the host matrix also with low loadings of additive. Carbon nanotubes are object of intensive studies between scientists and engineers because of their unique structural, chemical and physical characteristics which make them one of the most interesting materials for the production of innovative devices. Moreover their integration into composite structures allows to exploit their exceptional properties for the realization of more complex systems which can have various functionalities. Conducting Polymers (CPs) are organic conjugated polymers which show an intrinsic electrical conductivity at room temperature. This conductivity is due to the electrons systems delocalized on the principal polymer chain. CPs are very interesting materials which combine the high conductivity typical of the metals with the mechanical properties of the polymers, such as the flexibility and the possibility to be produced as thin films. All the materials prepared during the experimental work have been subjected to several morphological characterizations (such as Scanning Electron Microscopy, Transmission Electron Microscopy, Atomic Force Microscopy and Scanning Tunnelling Microscopy), structural characterizations (such as Raman spectroscopy and Electron Spin Resonance spectroscopy) and electrochemical characterizations (such as Chronoamperometry and Ciclic Voltammetry). Finally, functional characterizations have been performed with the aim to check the possibility to integrate the prepared materials into technological devices. The functional characterizations which have been tested include charge transport measurements, piezo-resistive measurements, photo-current measurements and microwave conductivity measurements. The thesis work demonstrates as the nanocomposites based on Carbon Nanotubes and Conducting Polymers can have useful and interesting applications in electro-mechanical and photovoltaic devices and as radar absorbent and electromagnetic shielding materials when all the steps regarding the composite realization (from synthesis to characterization) are controlled and reproducible

Mechanical characterization of polymer thin films by atomic force microscope based techniques

Polymeric thin films have been awakening continuous and growing interest for application in nanotechnology. For such applications, the assessment of their (nano)mechanical properties is a key issue, since they may dramatically vary between the bulk and the thin film state, even for the same polymer. Therefore, techniques are required for the in situ characterization of mechanical properties of thin films thatmust be nondestructive or only minimally destructive. Also, they must also be able to probe nanometer-thick ultrathin films and layers and capable of imaging the mechanical properties of the sample with nanometer lateral resolution, since, for instance, at these scales blends or copolymers are not uniform, their phases being separated. Atomic force microscopy (AFM) has been proposed as a tool for the development of a number of techniques that match such requirements. In this review, we describe the state of the art of the main AFM-based methods for qualitative and quantitative single-point measurements and imaging of mechanical properties of polymeric thin films, illustratin