1,721,060 research outputs found
Electrospun PHBV/PEO co-solution blends: Microstructure, thermal and mechanical properties
No full textWireless implantable and biodegradable sensors for postsurgery monitoring: Current status and future perspectives
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Electrospun poly(ε-caprolactone)-based composites using synthesized β-tricalcium phosphate
No full textNon-woven hybrid membranes based on poly(e-caprolactone) (PCL) and as-synthesized b-tricalcium phosphate
(b-TCP) were obtained by the electrospinning technique. A wide range of composition was investigated, the filler
content spanning between 2 and 60 wt%. The synthesis of the b-TCP powder was accomplished by titration of
calcium hydroxide with phosphoric acid followed by calcination of the resulting precipitate at 1100-C. The as-dried
calcium phosphate was characterized by Inductive Coupled Plasma (AES-ICP), thermal analysis (TG-DTA), Fourier
Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and high temperature X-ray
diffraction analysis (HT-XRD). The specific surface area (SSA) was evaluated by N2 adsorption. Microstructure
of PCL/TCP membranes was investigated by SEM, energy dispersion spectroscopy (EDS), XRD analysis, and SSA
measurements. The average fiber diameter ranged between 1 and 2 mm, the porosity was 80–90%, and the SSA
16m2/g. Mechanical properties were determined by uniaxial tensile test. A remarkable enhancement of the tensile
modulus was observed for composites containing up to 4 wt% b-TCP. The ultimate tensile strength ranged between
2 and 3MPa for samples loaded up to 8wt%. For most of the samples, the elongation at break was in the range
100–150
Mo-doped indium oxide films by dip-coating: synthesis, microstructure and optical properties
No full textMolybdenum doped indium oxide (In2−xMoxO3, IMO) is widely used in many electronic and optoelectronic devices due to its excellent electrical properties and optical transparency. In this work, a first attempt to produce IMO films by sol–gel dip coating was reported, starting from different reagents (i.e. indium nitrate or indium chloride and molybdenum chloride or ammonium molybdate as In and Mo sources, respectively). The influence of different reagents, solvents and annealing atmospheres (i.e. air and N2) on final coating properties was investigated in order to properly select the optimal process parameters. The morphological, microstructural and optical properties of the produced coatings were evaluated by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and UV–vis spectroscopy. The best performances, in terms of microstructure and transparency, were obtained for films produced by dip coating the indium nitrate and molybdenum chloride based solutions (In nitrate concentration 0.1–0.2 M), with the addition of a low amount of PEG, followed by annealing at 500 °C. The produced coatings consisted of monophasic In2O3 and were characterised by a uniform, homogeneous and cracks free surface, and high transmittance values in the vis range (i.e. 85–98%)
Effects of Humidity, Temperature and Bismuth Electrodeposition on Electroanalytical Performances of Nafion-coated Printed Electrodes for Cd2+ and Pb2+ Detection
No full textThe synergistic use of Nafion polymeric membrane and in situ electrodeposited bismuth film is a worthwhile strategy to develop electrochemical sensors for the detection of Cd2+ and Pb2+. However, Nafion thin films morphological and conductivity properties have a strong dependence on the environmental conditions, such as relative humidity and temperature, while the bismuth in situ electroplating can affect the repeatability of measurements. With the aim to overcome these drawbacks, the effects of the storage environmental conditions were investigated to improve the morphological stability and electroanalytical performances of Nafion film-based sensor for the detection of Cd2+ and Pb2+. Nafion-coated graphite-based screen-printed electrodes were stored at different humidity and temperature conditions and characterised by using square wave anodic stripping voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. Significant differences were observed at the varying of humidity conditions, with an enhancement of sensor electrochemical performances at lower humidity. Furthermore, different approaches for bismuth in situ electrodeposition on Nafion-coated screen-printed electrodes were compared by using overlap or removal approach. This study disclosed considerable differences in the electrochemical performances and morphology of the resulting bismuth-sensor, obtaining an enhancement of the working stability for the removal approach
Tailoring the properties of electrospun PHBV mats: co-solution blending and selective removal of PEO
No full textCarbon Black-Modified Electrodes Screen-Printed onto Paper Towel, Waxed Paper and Parafilm M®
Full text linkHerein, we evaluated the use of paper towel, waxed paper, and Parafilm M-(R) (Heathrow Scientific, Vernon Hills, IL, USA) as alternative substrates for screen-printed sensor manufacturing. Morphological study was performed to evaluate the adhesion of the ink on these uncommon substrates, as well as the morphology of the working electrode. The electrochemical characterization was carried out using ferricyanide/ferrocyanide as redox couple. To enhance the electrochemical properties of the developed sensors, the nanomaterial carbon black was used as nanomodifier. The modification by drop casting of the working electrode surface, using a stable dispersion of carbon black, allows to obtain a sensor with improved electrochemical behavior in terms of peak-to-peak separation, current intensity, and the resistance of charge transfer. The results achieved confirm the possibility of printing the electrode on several cost-effective paper-based materials and the improvement of the electrochemical behavior by using carbon black as sustainable nanomaterial
Design and development of advanced BaTiO3/MWCNTs/PVDF multi-layered systems for microwave applications
No full textDevelopment of absorbing materials at microwaves is of great interest in electronic and military applications, tuning their electromagnetic (EM) properties by varying their composition. In this paper, composite films based on polyvinylidene fluoride (PVDF), barium titanate (BaTiO3) nanoparticles and/or multiwalled carbon nanotubes (MWCNTs), were prepared. The innovative idea is to use strong dielectric (BaTiO3) and conducive (MWCNTs) fillers to tune the complex permittivity of the resulting material at microwaves (8.2-12.4 GHz). Moreover, on the basis of EM characterization, specific compositions were selected to produce multi-layered slabs by film stacking, exploiting the results of a numerical simulation, which provided information about the required compositions and thicknesses, and the order of the different layers. The designed slabs were realised and their properties compared with the simulated ones. It has been demonstrated that it is possible to gain the desired electromagnetic absorbing performance by alternating different compositions to suit a specific EM design
Silicon-substituted hydroxyapatite for biomedical applications
No full textSilicon-substituted hydroxyapatites (Si-HAps) have gained a lot of attention due to the improved bioactivity and biological responsiveness with respect to pure hydroxyapatite (HAp). This chapter presents a complete review of the Si-HAp and highlights the influence of the Si incorporation on the material characteristics and properties by describing its microstructure, sintering behavior, in vitro bioactivity, cellular response, and biomedical applications. In particular, this review starts with the description of the Si presence in the connective tissues and its influence on the bone cell metabolism. It continues through the synthesis procedures and the properties of Si-HAps in the form of powders, granules, scaffolds, and coatings. It focuses in detail on the investigation of the Si-HAps' bioactivity and biocompatibility, with an overview of the most important in vitro and in vivo studies. Finally, the last part of the chapter summarizes the documented clinical applications of Si-HAp and emphasizes some recent attempts to improve its bioactivity by designing biomimetic/smart materials based on it
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