Recent Advances in Carbon/Graphite Coatings

This Special Issue collects papers devoted to organic coatings based on polymers, graphene, and their combinations. These systems have great potentialities in the development of advanced materials for functional applications. In particular, graphene-based coatings on polymer substrates have interesting electrical characteristics, which are very sensible to the temperature and, therefore, they are very adequate for developing sensing materials and other types of functional materials

Program and the Book of abstracts / Eighteenth Young Researchers' Conference Materials Sciences and Engineering, December 4-6, 2019, Belgrade, Serbia

Young Researchers' meetings are held annually late in December since 2002 and they are organized by the Materials Research Society of Serbia. Originally conceived as seminars, since 2007 these meetings were transformed into conferences. The previous eleven meetings featured presentations based on the research of various young scientists from Serbia, Bosnia and Herzegovina, Montenegro, Slovenia, Brazil, Germany, United States of America, China, Poland, Belgium, Spain, Romania, United Kingdom, Austria, Italy, Hungary, Russia, Canada, etc. At the Conference, young researchers, students of doctoral, master and undergraduate studies, are given the opportunity to make an overview of their research into materials science and engineering through oral and poster presentations. As for the scientific content of the conference, we have given full priority to research topics that are currently considered as being on the frontier of the field. Nanotechnology and Advanced Materials, Synthesis and Engineering of Biomaterials, Application of Biomaterials, Theoretical Modeling of Materials and Advanced Methods for Synthesis and Processing present only some of those exciting topics that will be given the central stage and most attention during this meeting. The 18th Young Researchers' Conference Materials Science and Engineering was held in Belgrade, Serbia on December 4-6, 2019, Belgrade, Serbia. It was organized by the Materials Research Society of Serbia and Institute of Technical Sciences of the Serbian Academy of Sciences and Arts

Metal-Organic Frameworks for Sensing Applications in the Gas Phase

Several metal-organic framework (MOF) materials were under investigated to test their applicability as sensor materials for impedimetric gas sensors. The materials were tested in a temperature range of 120 °C - 240 °C with varying concentrations of O2, CO2, C3H8, NO, H2, ethanol and methanol in the gas atmosphere and under different test gas humidity conditions. Different sensor configurations were studied in a frequency range of 1 Hz -1 MHz and time-continuous measurements were performed at 1 Hz. The materials did not show any impedance response to O2, CO2, C3H8, NO, or H2 in the gas atmospheres, although for some materials a significant impedance decrease was induced by a change of the ethanol or methanol concentration in the gas phase. Moreover, pronounced promising and reversible changes in the electric properties of a special MOF material were monitored under varying humidity, with a linear response curve at 120 °C. Further investigations were carried out with differently doped MOF materials of this class, to evaluate the influence of special dopants on the sensor effect

Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT) for NOx storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2) during the short-term thermal NOx release

Metal organic frameworks with carbon black for the enhanced electrochemical detection of 2,4,6-trinitrotoluene

The sensing of explosives such as 2,4,6-trinitrotoluene (TNT) directly at an explosion site requires a fast, simple and sensitive detection method, to which electrochemical techniques are well suited. Herein, we report an electrochemical sensor material for TNT based on an ammonium hydroxide (NH4OH) sensitized zinc-1,4–benzenedicarboxylate Zn(BDC) metal organic framework (MOF) mixed with carbon black on a glassy carbon electrode. In the solvent modulation mechanism, by merely changing the concentration of NH4OH during synthesis, two Zn(BDC) MOFs with novel morphologies were fabricated via a hydrothermal approach. The as-prepared MOFs were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and high-resolution field emission electron microscopy (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS). The different morphologies of the MOFs, and their impact on the performance of the modified electrodes towards the electrochemical detection of TNT was investigated. Under optimum conditions, 0.7–Zn(BDC) demonstrated the best electrochemical response for TNT detection using square wave voltammetry (SWV) with a linear calibration response in the range of 0.3–1.0 M, a limit of detection (LOD) of 0.042 M, a limit of quantification (LOQ) of 0.14 M and a high rate of repeatability. Atomic-scale simulations based on density functional theory authenticated the efficient sensing properties of Zn(BDC) MOF towards TNT. Furthermore, the promising response of the sensors in real sample matrices (tap water and wastewater) was demonstrated, opening new avenues towards the real-time detection of TNT in real environmental samples

5th International Conference on Nanomaterials Science and Mechanical Engineering

No abstract available.publishe

Interfacial Behavior in Polymer Derived Ceramics and Salt Water Purification Via 2D MOS2

In the present dissertation, the behavior of the internal potential barrier in a polymer-derived amorphous SiAlCN ceramic was studied by measuring its complex impedance spectra at various dc bias as well as different testing and annealing temperatures. The complex impedance spectra of the polymer-derived a-SiAlCN were measured under various dc bias voltages in a temperature range between 50 and 150°C, as well as different annealing temperatures (1100-1400 °C). All spectra, regardless of temperature and bias, consist of two semi-circular arcs, corresponding to the free-carbon phase and the interface, respectively. The impedance of the free-carbon phase is independent of the bias, while that of the interface decreased significantly with increasing dc bias. It is shown that the change of the interfacial capacitance with the bias can be explained using the double Schottky barrier model. The charge-carrier concentration and potential barrier height were estimated by comparing the experimental data and the model. The results revealed that increasing testing temperature led to an increased charge-carrier concentration and a reduced barrier height, both following Arrhenius dependence, whereas the increase in annealing temperature resulted in increased charge-carrier concentration and barrier height. The phenomena were explained in terms of the unique bi-phasic microstructures of the material. The research findings reveal valuable microstructural information of temperaturedependent properties of polymer derived ceramics, and should contribute towards more precise understanding and control of the electrical as well as dielectric properties of polymer derived ceramics. Furthermore, the desalination performances and underlying mechanisms of two-dimensional CVD-grown MoS2 layers membranes have been experimentally assessed. Based on a successful large-area few-layer 2D materials growth, transfer and integration method, the 2D MoS2 layers membranes showed preserved chemical and microstructural integrity after integration. The few-layer 2D MoS2 layers demonstrated superior desalination capability towards various types of seawater salt solutions approaching theoretically-predicted values. Such performances are attributed to the dimensional and geometrical effect, as well as the electrostatic interaction of the inherently-present CVD-induced atomic vacancies for governing both water permeation and ionic sieving at the solution/2D-layer interfaces

Electroactive nanomaterials for environmental and pharmaceutical sensing

Sensing is an important emerging technology in the current industrial era. It covers a plethora of applications from medical personalized devices to aerospace oxygen level detectors. Of those applications, environmental and pharmaceutical sensors are significantly important. Specifically, electrochemical sensors are easy to use and develop besides being cost-effective and accurate. The work in this thesis concerns the development of two sensing platforms for the detection of Hg(II) as a water pollutant, and the detection of Lornoxicam (LOR) as a pharmaceutical compound. The materials fabricated were morphologically, structurally, and electrochemically characterized. They were also tested against their analytical targets in spiked and real sample media to ensure their utility, sensitivity and accuracy. The testing results were either in the sub-nano or the pico-molar levels, with high linear range. The materials were also examined to target the analyte species in separate and co-formulated media to assure their selectivity. Furthermore, the sensing platforms were repeatedly used to test their stability and reproducibility. Titania nanotubes/reduced graphene oxide (TNTs/RGO) showed an efficient sensibility of Hg(II) in the presence of Cu(II) and Mn(II) species with no significant interference for a wide range of concentrations. On the other hand, BaNb2O6 nanofibers showed an enhanced activity towards the electrocatalytic oxidation of Lornoxicam (LOR) and paracetamol (PAR), producing remarkably high oxidation currents. Wide linear dynamic ranges, high sensitivity, very low LOD, good reproducibility and repeatability, and high stability, together with simple procedures for surface modification and determination are the advantages of the prepared sensors

Surface Properties of Nanopore-Structured Metals and Oxides

The importance of understanding the properties of textured surfaces is growing with their potential wide engineering applications. In this thesis research, nanopore structures of metals and oxides were examined to determine the interactions between environmental object and the textured surfaces. The major applications of nanopore structures are micro/nanoelectromechanical systems (MEMS/NEMS), energy devices, sensors, and environmental devices. In order to achieve better performance in each, it needs to consider three critical surface properties such as surface forces, electrochemical performances, and wettability. In this research, the surface properties of nanopore structures have been explored with understanding the essence of contact. This research uses experimental approach combined with basic analysis in physical principles. Experiments include fabrication of nanopore structures, investigation of surface force, electrochemical evaluation, and wetting/electrowetting studies of nanopore structures. Metallic nanopore structures (MNSs) of nickel were characterized by using an atomic force microscope (AFM) and a triboscope. The mechanisms of bacteria desorption were examined by alumina nanopore structures (ANSs) with various pore sizes. The kinetics of ion-transfer on MNSs was studied using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltametry (CV). The (electro-) wetting behavior of MNSs were examined using a droplet shape measurement system. A physics based analysis was conducted in order to understand the principles of the nanopore effects on environments suitable for various applications. Results lead to the successful identification of critical geometrical factors. A contact model has been established to understand properties of textured surfaces. Specific design factors, which are related to the geometry of the textured surfaces has been identified. This research revealed fundamental mechanisms of contact and establish a relationship between morphology/geometry and surface properties. The findings in this thesis research afford new approach to optimize applications of textured surface. The proposed contact models are beneficial to the surface design and application of sustainable micro/nanodevices. This thesis includes eight chapters. The first chapter introduces the background and fundamental knowledge related to current research in order to understand the basics. Followed by the chapter two of motivation and objectives, chapter three discusses materials and experimental details, chapter four and five cover the surface forces, chapter six studies the electrochemical performances, chapter seven investigates the (electro-)wettability, and the conclusions and future recommendations are presented in chapter eight

Surface Properties of Nanopore-Structured Metals and Oxides

The importance of understanding the properties of textured surfaces is growing with their potential wide engineering applications. In this thesis research, nanopore structures of metals and oxides were examined to determine the interactions between environmental object and the textured surfaces. The major applications of nanopore structures are micro/nanoelectromechanical systems (MEMS/NEMS), energy devices, sensors, and environmental devices. In order to achieve better performance in each, it needs to consider three critical surface properties such as surface forces, electrochemical performances, and wettability. In this research, the surface properties of nanopore structures have been explored with understanding the essence of contact. This research uses experimental approach combined with basic analysis in physical principles. Experiments include fabrication of nanopore structures, investigation of surface force, electrochemical evaluation, and wetting/electrowetting studies of nanopore structures. Metallic nanopore structures (MNSs) of nickel were characterized by using an atomic force microscope (AFM) and a triboscope. The mechanisms of bacteria desorption were examined by alumina nanopore structures (ANSs) with various pore sizes. The kinetics of ion-transfer on MNSs was studied using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltametry (CV). The (electro-) wetting behavior of MNSs were examined using a droplet shape measurement system. A physics based analysis was conducted in order to understand the principles of the nanopore effects on environments suitable for various applications. Results lead to the successful identification of critical geometrical factors. A contact model has been established to understand properties of textured surfaces. Specific design factors, which are related to the geometry of the textured surfaces has been identified. This research revealed fundamental mechanisms of contact and establish a relationship between morphology/geometry and surface properties. The findings in this thesis research afford new approach to optimize applications of textured surface. The proposed contact models are beneficial to the surface design and application of sustainable micro/nanodevices. This thesis includes eight chapters. The first chapter introduces the background and fundamental knowledge related to current research in order to understand the basics. Followed by the chapter two of motivation and objectives, chapter three discusses materials and experimental details, chapter four and five cover the surface forces, chapter six studies the electrochemical performances, chapter seven investigates the (electro-)wettability, and the conclusions and future recommendations are presented in chapter eight