<p> Optical metamaterials have triggered extensive studies driven by their fascinating electromagnetic properties that are not observed in natural materials. Aside from the extraordinary progress, challenges remain in scalable processing and material performance which limit the adoption of metamaterial towards practical applications. The goal of this dissertation is to design and fabricate nanocomposite thin films by combining nitrides with a tunable secondary phase to realize controllable multi-functionalities towards potential device applications. Transition metal nitrides are selected for this study due to the inherit material durability and low-loss plasmonic properties that offer stable two-phase hybridization for potential high temperature optical applications. Using a pulsed laser deposition technique, the nitride-metal nanocomposites are self-assembled into various geometries including pillar-in-matrix, embedded nanoinclusions or complex multilayers, that possess large surface coverage, high epitaxial quality, and sharp phase boundary. The nanostructures can be further engineered upon precise control of growth parameters. </p><p> This dissertation is composed of a general review of related background and experimental approaches, followed by four chapters of detailed research chapters. The first two research chapters involve hybrid metal (Au, Ag) - titanium nitride (TiN) nanocomposite thin films where the metal phase is self-assembled into sub-20 nm nanopillars and further tailored in terms of packing density and tilting angles. The tuning of plasmonic resonance and dielectric constant have been achieved by changing the concentration of Au nanopillars, or the tuning of optical anisotropy and angular selectivity by changing the tilting angle of Ag nanopillars. Towards applications, the protruded Au nanopillars are demonstrated to be highly functional for chemical bonding detection or surface enhanced sensing, whereas the embedded Ag nanopillars exhibit enhanced thermal and mechanical stabilities that are promising for high temperature plasmonic applications. In the last two chapters, dissimilar materials candidates beyond plasmonics have been incorporated to extend the electromagnetic properties, include coupling metal nanoinclusions into a wide bandgap semiconducting aluminum nitride matrix, as well as inserting a dielectric spacer between the hybrid plasmonic claddings for geometrical tuning and electric field enhancement. As a summary, these studies present approaches in addressing material and fabrication challenges in the field of plasmonic metamaterials from fundamental materials perspective. As demonstrated in the following chapters, these hybrid plasmonic nanocomposites provide multiple advantages towards tunable optical or biomedical sensing, high temperature plasmonics, controllable metadevices or nanophotonic chips.</p><div><br></div>

<p>  </p> <p>Graphene is a two-dimensional (2-D) sheet of <em>sp2</em> hybridized carbon atoms with extraordinary thermal, electrical, and mechanical properties. Among numerous sophisticated and costly synthesis techniques including chemical vapor deposition (CVD), SiC and microwave plasma; liquid-phase exfoliation (LPE) has been one of the most widely used techniques for low-cost and large scale graphene synthesis since it was first reported in 2008. LPE involves the use of liquid media to exfoliate graphite precursors directly into mono- or few-layered graphene. Stable dispersions of few-layered graphene are desirable for thin-film deposition on a large scale but are limited by the use of polar organic solvents with high boiling points and unfavorable toxicity profiles. This limitation can be overcome by milling and exfoliation of graphene nanoplatelets (GrNPs) in ethyl acetate (EtOAc) and acetone, volatile solvents with low toxicity profiles and modest environmental impact. Solvent-assisted grinding of pristine GrNPs on a horizontal ball mill followed by sonication produces concentrated suspensions up to 356 µg/mL that remain stable at room temperature for a minimum of 6 weeks without the addition of surfactants. Exfoliated graphene layers have an average thickness of 4.5 nm which corresponds to 10–12 layers of graphene on Si/SiO2 substrates. EtOAc and acetone-based dispersions of exfoliated graphene can be deposited uniformly using conventional airbrush equipment as low-boiling point solvents evaporates instantaneously after deposition. This deposition method also provides freedom regarding to target substrate and overcomes any substrate related limitations observed in other techniques. Practical demonstrations of spray-coated graphene films include (i) conductive surfaces with sheet resistance as low as 1 kΩ/sq, and (ii) solid contacts for disposable and low-cost nitrate-selective electrodes, with high reproducibility in the voltage readouts across multiple sensors.</p>

Particle dispersions provide a promising tool for the engineering of functional materials that exploit self-assembly of complex structures. Dispersion made from magnetic colloidal particles is a great choice; they are biocompatible and remotely controllable among many other advantages. However, their dominating dipolar interaction typically limits structural complexity to linear arrangements. This paper shows how a magnetostatic equilibrium state with noncollinear arrangement of the magnetic moments, as reported for ferromagnetic Janus particles, enables the controlled self-organization of diverse structures in two dimensions via constant and low-frequency external magnetic fields. Branched clusters of staggered chains, compact clusters, linear chains, and dispersed single particles can be formed and interconverted reversibly in a controlled way. The structural diversity is a consequence of both the inhomogeneity and the spatial extension of the magnetization distribution inside the particles. We draw this conclusion from calculations based on a model of spheres with multiple shifted dipoles. The results demonstrate that fundamentally new possibilities for responsive magnetic materials can arise from interactions between particles with a spatially extended, anisotropic magnetization distribution.

Différents matériaux hybrides à base de polyoxométallates (POMs) ont été synthétisés au cours de cette thèse. Dans un premier type de matériaux, appelé POM@MOF, des POMs sont incorporés au sein des cavités poreuses d'un Metal-Organic-Framework (MOF). Ces matériaux ont été synthétisés par une méthode d'imprégnation en milieu aqueux ou par synthèse directe en conditions solvothermales. Ils ont ensuite été caractérisés de manière approfondie. La stabilité ou l'évolution des polyoxométallates lors de l'incorporation dans le MOF étant chaque fois parfaitement établie. Les matériaux POM@MOFs ont ensuite été étudiés pour leurs applications en magnétisme, pour la détection et en catalyse. Dans un second temps, des polymère de coordination hybrides à base de POMs (surnomés POMOFs) construits à partir d'isomères ε-Keggin reliés par des ligands organiques ont été synthétisés par voie hydrothermale. De nouvelles structures POMOFs ont pu être obtenue en présence de POMs, de ligands carboxylates et de complexes métalliques comme contre-ions non-innocents. L'activité de ces matériaux vis-à-vis de la réduction des protons a été étudiée par électrocatalyse et photocatalyse. Parallèlement, des synthèses de composés moléculaires solubles à base de POMs ε-Keggin ont également été réalisées. Finalement, des espèces hybrides incorporant des métaux de transitions et des ligands bisphosphonates ont été synthétisées : des polymères incorporant du cuivre(II) et un composé moléculaire à base fer(III). Ces espèces ont ensuite été étudiées pour leurs propriétés magnétiques, catalytiques pour la réduction des NOx. L'espèce à base de fer a également été sélectionnée comme substrat pour des études de dépôt sur surface de silice. / Different Polyoxometalate (POM) based hybrid materials were synthesised during this doctorate. In the first type of materials, called POM@MOF, POMs are incorporated in the porous cavities of a Metal-Organic-Framework (MOF). These materials were synthesised by a impregnation method in an aqueous medium or by direct synthesis in solvothermal conditions. They were then extensively characterised. For every material, the stability or transformation of the POMs during the incorporation was accurately established. The POM@MOFs materials were then studied for their applications in magnetism, for detection and in catalysis. In a second time, POM-based hybrid coordination polymers (called POMOFs) made from ε-Keggin isomers connected by organic linkers were synthesised by a hydrothermal method. New POMOFs structures have been obtained with POMs, carboxylate linkers and metallic complexes as non-innocents counter ions. The catalytic activity of these materials toward protons reduction was studied by electrocatalysis and photocatalysis. In parallel, syntheses of soluble molecular compounds based on ε-Keggin POMs were also performed. Finally, hybrid species incorporating transition metals and bisphosphonate linkers were synthesised : three copper(II) based polymers and a molecular coumpound incorporating iron(III). The magnetic and catalytic (reduction of NOx) properties of these materials were then studied. The iron based species was also selected as substrate for the deposition on a silica surface.

<p>Passive chipless wireless sensors have gained great attention in Radio Frequency Identification (RFID) applications, inventory tracking, and structural health monitoring, as they offer a prospective low-cost, scalable alternative to the state-of-the-art active sensors. While the popularity and demand for chipless sensors are on the rise, their applications are limited to low-noise environments and their caliber as low-cost, scalable devices has not been explored to a successful degree in challenging domains, such as precision agriculture, healthcare, and food packaging. Size, cost of materials, and complexity of the manufacturing process are the main obstacles to progress in the large-scale production of chipless sensors for practical applications. </p> <p><br></p> <p>Conventional manufacturing processes, such as photolithography, are costly, cumbersome, and time intensive. While additive manufacturing techniques, such as printing technologies, have circumvented some of these challenges, printing techniques require costly inks and complex post-processing steps, such as drying and sintering, which limit their large-scale utilization. To overcome these challenges, this dissertation focuses on investigating the possibility of utilizing laser processing of conventional metalized films and polymers to develop cost-effective chipless sensors. This Scalable Laser Assisted Manufacturing (SLAM) process offers a platform for large-scale roll-to-roll production of high-resolution sensors for precision agriculture, healthcare, and food packaging applications. </p> <p><br></p> <p>In this pursuit, the first study explores combining the SLAM process with 3D printing to develop a miniaturized, biodegradable, chipless sensor for soil moisture monitoring. In the second study, the SLAM process is further explored in the development of metalized stickers for healthcare applications focusing on urine bag management and early risk detection of urinary tract infections. In the third study, the capability of the SLAM process to form moisture-sensitive metal nanoparticles as a co-product of metal patterning is harnessed to develop a chipless humidity sensor. The SLAM process is further expanded in the fourth study by functionalizing metalized films with stimuli-responsive polymers to achieve specificity in detecting unique biomarkers of food spoilage. The SLAM platform described in this work opens up new avenues toward processing metalized fabric for the future of wearable electronics and implementing multi-functional sensors for precision agriculture.</p> <p>  </p>

No description available.

The ferromagnetic shape memory alloy, Fe7Pd3, not only offers promising applications, but also reveals a number of unresolved scientific questions, including coupling between a series of martensite and order–disorder transitions, which are in the focus of the present study. To address and understand these aspects, which are of particular importance for controlling phase stability in Fe7Pd3, an ab initio based Monte Carlo simulation code is developed, whose results demonstrate that equilibrated ordered or disordered phases show distinct dependencies coupled to temperature and lattice structure. Moreover, in equiatomic domains emerging from initially randomized disorder, an intermediate, entropy stabilized phase is identified with significantly higher magnetic anisotropy energy, being advantageous for miniaturized applications. This phase, among other observed configurations, is comprehensively characterized by free energy landscapes and magneto-structural coupling derived from vibrational analysis of molecular dynamics trajectories and full relativistic spin polarized density functional theory ground state calculations, respectively.

<p>Fully portable, rapid, and user-friendly sensors can successfully lead to the continuous monitoring of toxins present in the ecosystem as well as the detection of biomarkers to prevent diseases. Towards this goal, we explore electrochemical and colorimetric methods to develop platforms for the on-site detection of pesticides, heavy metals, and inflammation biomarkers. </p> <p>This thesis presents work with the primary aim of developing non-biological and biological-based platforms. Chapter 2 describes a fully roll-to-roll electrochemical sensor with high sensing and manufacturing reproducibility for detecting nitroaromatic organophosphorus pesticides (NOPPs). This sensor is based on a flexible, screen-printed silver electrode modified with a graphene nanoplatelets coating and a zirconia coating. This chapter outlines the evaluation of the electrocatalytic activity of zirconia towards the reduction of NOPPs, using methyl parathion as a pesticide sample. Furthermore, it describes the fundamentals of electrochemistry focused on voltammetry techniques used for surface characterization and quantification. The topics reviewed serve as the first step to further manufacturing sensors through large-scale methods (e.g., roll-to-roll). Chapter 3 describes the development of a dual-modality sensing system for the detection of mercury in river waters with high accuracy and precision. The objective of this project was to incorporate colorimetric platforms into the electrochemical methods to create a dual detection design and avert false positives and negatives. Here, novel bio-functional aptamers were incorporated in a sensor containing a paper test that detects mercury by a color change and an electrochemical test that measures charge transfer resistance changes upon aptamer-target interaction. For this platform, the colorimetric test demonstrates the utilization of two systems that consist of silver and gold citrate-capped nanoparticles bio-functionalized with highly specific aptamers. The mechanism of detection of these two systems is through Ps-AgNPs and Ps-AuNPs aggregation as a result of ssDNA-Hg2+ interaction. Using Ps-AuNPs microparticles, Chapter 4 describes a fully colorimetric and smartphone-based biosensor for detecting cardiac troponin T, a biomarker for diagnosing acute myocardial infarction. Here, a comparison in detection performance between Whatman grade 1 and high-flow filter paper is reviewed. Finally, Chapter 5 evaluates the colorimetric detection performance of Ps-AuNPs microparticles towards imidacloprid and carbendazim, two of the pesticides most found in imported produce in the United States. The chapter compares gold-based microparticles in which different aptamers were immobilized, and image acquisition approaches.</p> <p>All sensors reported in this thesis are especially suitable for environmental contaminants monitoring or point-of-care diagnosis applications. The materials selection, use or synthesis, and platforms’ performance optimization, development, and feasibility for scale-up manufacturing are expected to advance on-site biosensing technologies and their commercialization.</p>

Globally the combustion of fossil fuels has increased to a greater extent. Carbon dioxide (CO2) a major greenhouse gas isa by-product of such combustion practices. Increase in the quantity of CO2 emissions has resulted in serious environmental issues including global warming, ocean acidification, extreme weather, and much more leaving a direct impact on the human society. To reduce these emissions, we need a more efficient carbon dioxide capturing technology. Using advances in materials science and engineering we can develop newer technologies for the capture of carbon dioxide gas. Metal-organic frameworks (MOFs) constitute a class of three-dimensional porous materials. They have shown applicability in various fields including carbon dioxide capture. A vast variety of MOFs can be synthesized by selecting proper metal salts and organic-linkers to build up the MOF structure. This thesis focuses on the synthesis of MOFs through a sustainable process or green synthesis route. Most of the MOFs in this study have been synthesized at ambient temperature and pressure conditions with deionized water as the primary solvent. A total of eight MOFs were synthesized in this study using two organic-linkers namely, 1,2,4,5-tetrakis(4-carboxyphenyl)-benzene (H4TCPB) and 2,5-dihydroxy-1,4-benzoquinone (H2DHBQ). The metal-salts used were based on hafnium, zirconium, cerium, magnesium, iron and manganese. A number of qualitative and quantitative tests were carried out onthe MOF samples to ensure their quality of produce and performance. The primary focus was to test the materials for their capacity to uptake carbon dioxide (CO2) in a mixture of flue gases. The highest CO2 uptake capacity was recorded to be 3.02 mmol/g (at 293 K and 1 bar) by the H2DHBQ-magnesium based MOF. All the materials showed good results andwere proven to be reusable. All the synthesized MOFs were crystalline in nature, showed a single-phase microstructure and high surface area values. A supplementary study was conducted wherein the powdered MOFs were 3D printed by the Direct Ink Writing (DIW) technique using an alginate binder. The study was satisfactory because the MOFs after being 3D printed, managed to preserve their inherent properties and characteristics. The results were in par with that of their pristine MOF counterparts. / Den globala förbränningen av fossila bränslen har i allt större utsträckning ökat. Koldioxid (CO2) är en avde viktigast växthusgaserna och erhålls som biprodukt från många förbränningsmetoder. Den höga haltenkoldioxid i atmosfären har resulterat i allvarliga miljömässiga konsekvenser inklusive den globaluppvärmningen, försurning av haven, extremt väder och mycket mer som har en direkt påverkan på detmänskliga samhället. För att minska dessa utsläpp behöver vi en mer effektiv koldioxidinfångningsteknologi. Med hjälp av framsteg inom materialvetenskapen kan vi utveckla nyare tekniker för att fångakoldioxid.  Metallorganiska ramverk (MOFs) utgör en klass av tredimensionella porösa material. De har visat siganvändbara inom olika områden inklusive infångning av koldioxid. Många variation av MOF material kansyntetiseras från olika metallsalter och organiska ligander för att bygga upp MOF-strukturen. Dettaexamensarbete fokuserar på syntesen av metallorganiska ramverk via en grön syntesväg och en hållbarprocess. En stor del av MOF materialen som erhölls syntetiserades i rumstemperatur och vid normala tryckmed avjoniserat vatten som det primära lösningsmedlet. Åtta MOFs material syntetiserades i detta projekt med två olika organiska ligander, nämligen, 1,2,4,5-tetrakis(4-karboxifenyl)bensen (H4TCPB) och 2,5-dihydroxy-1,4-bensokinon (H2DHBQ). Metallsalternasom användes i synteserna baserades på hafnium(IV), zirkonium(IV), cerium(IV), magnesium(II), järn(II)och mangan(II). Ett antal kvalitativa och kvantitativa tester genomfördes på MOF:arna för att säkerställaderas kvalitet och prestanda. Det primära fokuset var att testa de olika materialen för deras förmåga att taupp koldioxid (CO2) i en blandning av olika gaser (så som kväve, N2). Den DHBQ-magnesium-baseradeMOF:en uppvisade den högsta CO2-upptagningsförmågan som var 3,02 mmol/g. Alla MOF material visadegoda resultat och visade sig även vara återanvändbara. Alla syntetiserade MOF:ar hade god kristallinitet,uppvisade en singulär fas samt hög ytarea. En kompletterande studie genomfördes där de syntetiserade MOFs materialen (i dess pulverform) 3Dprintades med hjälp av natriumalginat som bindemedel. Studien var lyckad eftersom MOF:arna erhöll entillämplig form/maktrostruktur samtidigt som materialen bevarade sina inneboende egenskaper efter 3Dprintningen.

<p dir="ltr">Phosphor thermography is an effective technique for making spatially resolved temperature measurements on surfaces, however little consideration has been given to incorporating the phosphors inside crystalline materials to make internal measurements. Doing so would grant optical access to the phosphors through the crystal. In this work, we prepared a thermographic energetic composite via fast crash encapsulation of BaMgAl₁₀O₁₇:Eu (BAM) in ammonium perchlorate (AP) crystals, which enabled the use of phosphor thermography to spatially resolve the temperature of the energetic composite. We demonstrate that the temperature measurements show good agreement with thermocouple measurements. The ability to calibrate the material was also demonstrated and compared to the response in dynamic thermal environments. Usability limits as well as thermal stability issues of the composite were also investigated and discussed. The successful encapsulation of BAM within AP and demonstration of thermographic behavior in the composite, indicate the viability of using encapsulation as a method to produce thermographic energetic composites.</p>