Functionalized magnetoelastic resonant platforms for chemical and biological detection purposes

211 p.In recent years, research on magnetoelastic materials has focused on their applications as sensors to observe, measure and control different kind of physical, chemical and biological parameters, taking advantage of the remote query and answer of this kind of materials. In order to use those magnetoelastic materials for sensing purposes, they must be coated with an active layer which will be the responsible of selectively detect and trap the target molecule or analyte desired to be detected. This thesis work is devoted to different functionalization processes performed using different active materials as a polymer, ZnO or zeolites onto magnetoelastic materials. Polystyrene depositions allowed studying the main two parameters affecting the detection process, the sensitivity and the quality factor. By following the change on the resonance frequency with the deposited polymer mass it has been probed that the linearity of the detection process can be applied just for small-deposited mass changes.Different methods to form a homogenous ZnO film onto the magnetoelastic material were tried. Finally, ZnO depositions were performed by casting a nanoparticle suspension onto the Metglas materials. This allowed to measure by using the resonance-antiresonance method the Young modulus of the ZnO deposited film. As ZnO is biocompatible and allows protein immobilization, a H2O2 sensor was fabricated by pinning hemoglobin onto the ZnO layer. Hemoglobin reacts with hydrogen peroxide, which plays an important role in some physiological and biological processes. The response of the sensor was followed for first time by using simultaneously two methods, the magnetoelastic resonance method in order to study the evolution of the resonance frequency and by cyclic voltammetry measurements as the reaction between H2O2 and hemoglobin is electrochemical.The third material used to functionalize the resonant platforms were zeolites. Three different zeolites, LTA, FAU and MFI were hydrothermally synthesized onto a homemade magnetoelastic material in order to use those systems as sensor for o-xylene detection.BC Materials:basque center for materials, applications & nanostructure

MEMS Devices for Miniaturized Gas Chromatography

In the era of the Internet of Things, the need for mobile devices able to analyze accurately real samples with sometimes very small volumes is a must. Gas chromatography (GC) is a common laboratory technique widely used for analyzing semi-volatile and volatile compounds. However, this technique is not suitable to be used outside labs. The development of micro-machined processes encouraged the development of miniaturized gas chromatographs. This chapter focuses on the recent development in the field of miniaturized gas chromatography and its component up to the present in various fields of analyses

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

Printing Technologies on Flexible Substrates for Printed Electronics

Printing technologies have been demonstrated to be highly efficient and compatible with polymeric materials (both inks and substrates) enabling a new generation of flexible electronics applications. Conductive flexible polymers are a new class of materials that are prepared for a wide range of applications, such as photovoltaic solar cells, transistors molecular devices, and sensors and actuators. There are many possible printing techniques. This chapter provides an opportunity to review the most common printing techniques used at the industrial level, the most commonly used substrates and electronic materials, giving an overall vision for a better understanding and evaluation of their different features. Several technological solutions (contact/noncontact) and its critical challenges are also presented. Inkjet Printing Technology (IPT) has been receiving a great attention and therefore higher focus is given to this technology. An overview of IPT is presented to evidence its importance and potential as a key-technology on the research field for printed electronics development, as well as on large scale industrial manufacturing. A background and a review on prior work are presented along with used materials, developed applications and potential of IPT technology. The main features of the different printing technologies, advantages and main challenges are also compared

Nanomembrane: A New MEMS/NEMS Building Block

Since nanomembranes are a novel concept which extends the range of MEMS & NEMS building blocks and practically introduces a new one, this means that whole branches of science and technology can be re-read and re-created through it, which may create an enormous number of novel applications. Nanomembranes need to be incorporated into coherent and ambitious programs of nanotechnology research, with aggressive funding and awareness-increasing campaigns. A care should be taken at that both about the fundamental and the applied aspects of research, since the recent developments clearly indicate that the field may have many promises and even surprises in stock. A development of a novel technology or concept very rarely follows a smooth and gradual trend. Much more often one encounters an abrupt surge in development after the necessary conditions are met, not only scientific and technological, but also social and economic. In our opinion such is the situation with nanomembranes at the beginning of the 21st Century

Carbon Nanomaterials and their application to Electrochemical Sensors: A review

Carbon has long been applied as an electrochemical sensing interface owing to its unique electrochemical properties. Moreover, recent advances in material design and synthesis, particularly nanomaterials, has produced robust electrochemical sensing systems that display superior analytical performance. Carbon nanotubes (CNTs) are one of the most extensively studied nanostructures because of their unique properties. In terms of electroanalysis, the ability of CNTs to augment the electrochemical reactivity of important biomolecules and promote electron transfer reactions of proteins is of particular interest. The remarkable sensitivity of CNTs to changes in surface conductivity due to the presence of adsorbates permits their application as highly sensitive nanoscale sensors. CNT-modified electrodes have also demonstrated their utility as anchors for biomolecules such as nucleic acids, and their ability to diminish surface fouling effects. Consequently, CNTs are highly attractive to researchers as a basis for many electrochemical sensors. Similarly, synthetic diamonds electrochemical properties, such as superior chemical inertness and biocompatibility, make it desirable both for (bio) chemical sensing and as the electrochemical interface for biological systems. This is highlighted by the recent development of multiple electrochemical diamond-based biosensors and bio interfaces

Functionalized magnetoelastic resonant platforms for chemical and biological detection purposes

211 p.In recent years, research on magnetoelastic materials has focused on their applications as sensors to observe, measure and control different kind of physical, chemical and biological parameters, taking advantage of the remote query and answer of this kind of materials. In order to use those magnetoelastic materials for sensing purposes, they must be coated with an active layer which will be the responsible of selectively detect and trap the target molecule or analyte desired to be detected. This thesis work is devoted to different functionalization processes performed using different active materials as a polymer, ZnO or zeolites onto magnetoelastic materials. Polystyrene depositions allowed studying the main two parameters affecting the detection process, the sensitivity and the quality factor. By following the change on the resonance frequency with the deposited polymer mass it has been probed that the linearity of the detection process can be applied just for small-deposited mass changes.Different methods to form a homogenous ZnO film onto the magnetoelastic material were tried. Finally, ZnO depositions were performed by casting a nanoparticle suspension onto the Metglas materials. This allowed to measure by using the resonance-antiresonance method the Young modulus of the ZnO deposited film. As ZnO is biocompatible and allows protein immobilization, a H2O2 sensor was fabricated by pinning hemoglobin onto the ZnO layer. Hemoglobin reacts with hydrogen peroxide, which plays an important role in some physiological and biological processes. The response of the sensor was followed for first time by using simultaneously two methods, the magnetoelastic resonance method in order to study the evolution of the resonance frequency and by cyclic voltammetry measurements as the reaction between H2O2 and hemoglobin is electrochemical.The third material used to functionalize the resonant platforms were zeolites. Three different zeolites, LTA, FAU and MFI were hydrothermally synthesized onto a homemade magnetoelastic material in order to use those systems as sensor for o-xylene detection.BC Materials:basque center for materials, applications & nanostructure