This thesis covers fundamental aspects of process control when growing titanium oxide nanoparticles in a reactive sputtering process. It covers the influence of oxygen containing gas on the oxidation state of the cathode from which the growth material is ejected, as well as its influence on the particles oxidation state and their nucleation. It was found that a low degree of reactive gases was necessary for nanoparticles of titanium to nucleate. When the oxygen gas was slightly increased, the nanoparticle yield and particle oxygen content increased. A further increase caused a decrease in particle yield which was attributed to a slight oxidation of the cathode. By varying the oxygen flow to the process, it was possible to control the oxygen content of the nanoparticles without fully oxidizing the cathode. Because oxygen containing gases such as residual water vapour has a profound influence on nanoparticle yield and composition, the deposition source was re-engineered to allow for cleaner and thus more stable synthesis conditions. The size of the nanoparticles has been controlled by two means. The first is to change electrical potentials around the growth zone, which allows for nanoparticle size control in the order of 25-75 nm. This size control does not influence the oxygen content of the nanoparticles. The second means of size control investigated was by increasing the pressure. By doing this, the particle size can be increased from 50 – 250 nm, however the oxygen content also increases with pressure. Different particle morphologies were found by changing the pressure. At low pressures, mostly spherical particles with weak facets were produced. As the pressure increased, the particles got a cubic shape. At higher pressures the cubic particles started to get a fractured surface. At the highest pressure investigated, the fractured surface became poly-crystalline, giving a cauliflower shaped morphology.

The purpose of this research project was to study the αᵧ phase in Alnico 6. Other phases were studies for comparison. Also the effect of an applied magnetic field on the formation of the αᵧ phase was investigated. Three single crystals of Alnico 6 were heat treated for one hour—one at 1250°C, one at 1000°C, and one at 800°C—and water-quenched. The microstructure of each sample was observed with the optical microscope, and X-ray diffraction patterns were taken to determine the crystal structure of the phases present. Several single crystal samples of Alnico 6 were heat treated at 1000°C and furnace-cooled. Some of the samples were heat treated and furnace-cooled in the presence of an applied magnetic field of about 5000Oe, and the others were heat treated and furnace-cooled without an applied magnetic field. Each set of samples were electrothinned, and the microstructure of the αᵧ and α₁ ₊ α₂ phases was studied using the electron microscope. Electron diffraction patterns and electron micrographs were taken from αᵧ regions and α₁ ₊ α₂ regions of each sample. By a combination of X-ray and electron diffraction, it was determined that the crystal structure of the α, α₁, α₂ and αᵧ phases is body-centered cubic, with a lattice parameter of 2.87 Å. Electron diffraction showed that the crystal structure of the combined α₁ ₊ α₂ phases is ordered body-centered cubic, and that the lattices of these two phases are coherent. Other investigators have found that only the α₁ phase is ordered in Alnico 5 and Alnico 8 and thus is believed be the case in Alnico 6 also. Electron diffraction showed the αᵧ phase to be ordered, with the degree of ordering less than that in the α₁ phase. Some difference was noted between the αᵧ phase formed with a magnetic field and that formed without a magnetic field. The αᵧ formed with a magnetic field showed twinning and some small lattice rotations, while stat formed without a field did not. The reason for this is not known.

Superkondensatorer är energilagringsenheter som har uppmärksammats mer under det senaste decenniet. Några av de fördelar som dessa enheter har varit är lagring av hög effekttäthet, förlängda livscykler och snabba laddnings- och urladdningstider. Dock är superkondensatorer fortfarande begränsade i energitäthet i jämförelse med batterier. För att få högre effekt och energitäthet är en asymmetrisk hybrid superkondensator ett bra alternativ. Denna enhet består av en kolbaserad elektrod för icke-faradaiska reaktioner och en kolelektrod kombinerad med metalloxider för redoxreaktioner. Materialvalet spelar en avgörande roll för förmågan en hybrid asymmetrisk superkondensator ska ha. I denna studie undersöks fyra olika kommersiella kol. Den specifika ytan, porstorlekarna och morfologin jämförs. Dessutom syntetiseras metalloxidernanopartiklar MnO2 och kristallstrukturen undersöks. Därtill beläggs MnO2-partiklarna på de fyra kolen och tillväxten av dessa undersöks. Slutligen analyseras interaktionen mellan jonvätskan 1-butyl-3-metylimidazoliumtetrafluorborat (BMIM[BF4]) som en elektrolyt och de olika kolen. / Supercapacitors are energy storage devices that have drawn attention for the past decade. Some of the advantages of these devices are higher power density storage, extended life cycles, and fast charge and discharge times. However, supercapacitors are still limited in energy density compared to batteries. To obtain higher power and energy densities, a hybrid asymmetric supercapacitor is a good alternative. This device consists of one carbon-based electrode for non-faradaic reactions, and one carbon electrode combined with metal oxides for redox reactions. The material choice is important for the capability of a hybrid asymmetric supercapacitor. In this study, four different commercial carbons are investigated. The specific surface area, pore sizes, and morphology are compared. In addition, metal oxide nanoparticles MnO2 are synthesised, and crystal structure is investigated. Furthermore, the MnO2 particles are deposited on the four carbons and the growth of those is studied. Finally, the interaction between ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF4]) as an electrolyte and the different carbons is studied.

Modified nanocellulose have distinctive qualities and have drawn a lot of interest from a variety of fields. It is a natural, sustainable product that is manufactured from plant-based materials like wood and other renewable resources. It is also biodegradable. It is a possible material for battery separators because of its great mechanical strength, flexibility, and ability to create a stable and consistent membrane. Due to the cost of using it as a membrane, it has been investigated in this work to see if it can be coated onto a substrate and used as battery separator. In this work sulfonated cellulose nanofibrils (SCNF) has been used to be coated on kraft paper and inkjet paper using a rod coater. Parameters like concentration, thickness and substrates have been varied in this experiment. Viscosity was measured using Brookfield instrument to measure the viscosity for 0,5% SCNF and 1,5% SCNF. The coating was carried out using a rod coater and varying between two rods to influence the thickness, the coating used concentrations of 0,5% SCNF and 1,5% SCNF and two different substrates, kraft paper and inkjet paper. Thickness was determined to study the effect of the variation in rod. The mechanical strength was tested on the coated paper substrates and compared the results to the noncoated substrates as reference, the mechanical strength showed an improvement with the coated SCNF substrates. Permeance through the Gurley method was studied in order to understand how the coated substrates behaves compared to the noncoated. Contact angle was determined as well to understand the wettability of the coated substrates and how they would behave as separators in zinc ion batteries. The contact angle decreased with increasing concentration of the SCNF which is a result of the sulfonate groups. Cross sections were analyzed using SEM to study the influence of the coating to the substrates. Ionic conductivity was also tested to evaluate the possibility of the coated substrates as separators.

Fuel cells play a key role in implementing hydrogen as alternative fuel to eliminate CO2-emissions and their performance is largely dependent on the contact resistance of the surface of bipolar plates. For stainless steel bipolar plates titanium carbonitride coatings were suggested for modifying surface properties and thereby reducing contact resistance while maintaining mechanical strength. This study analysed Ti(C,N) coatings with different carbon content in terms of composition, microstructure chemical bonding and contact resistance. The films were deposited either by reactive co-sputtering from a titanium and a graphite target under nitrogen flow or by co-reactive sputtering from a titanium target under flow of nitrogen and methane. It was found that an increase in carbon content results in a nanocomposite of Ti(C,N) and an amorphous carbon (a-C) matrix leading to nanocrystalline films with a smooth surface. Analysing the amount of a-C as a functions of overall carbon content, it is observed that carbon is more effectively incorporated into carbonitride grains when using methane gas as a carbon source. Furthermore, the contact resistance of the titanium carbonitride coatings was found to be lowest (below 10 mΩ) for a small amount of a-C phase and overall lower than that of carbide and nitride reference samples. Therefore, titanium carbonitrides are a promising coating material for electrical contact applications such as fuel cells.

The pursuit of sustainable and high-performance materials is of utmost significance in driving the progress of battery technologies. Solid-state technology represents a promising avenue for the development of batteries with improved sustainability and performance. In this context, the present study delves into the examination of composition and the substitution of oxygen with nitrogen within the 50Li2O-xSiO2-(50-x)P2O5 glass system, specifically as applied to Solid-State electrolytes. The objective is to evaluate the influence of these factors on the electrical properties of the glass and their potential implications for Solid-State battery technology. The glass matrix was obtained through the melt-quenching technique, followed by comprehensive characterization using electrochemical impedance spectroscopy. The influence of varying silica content on the conductivity of the glass was investigated. This led to the selection of the glass system with the highest conductivity for further experiments involving nitridation. Subsequent experiments on nitridation aimed to explore the impact of nitrogen incorporation on the conductivity of the glass. By systematically varying the nitrogen content at different temperatures, the study sought to elucidate the relationship between nitrogen content and the resulting increase in glass conductivity.    The study reveals a noteworthy finding regarding the impact of nitrogen content on the conductivity of the glass. Specifically, when the nitrogen content was increased, the conductivity increased. In the case of a similar glass composition in pellet form, the conductivity at room temperature increased from Log σ = -8,009 (for glass without nitrogen) to Log σ = -6,951 (for nitrided glass). Additionally, the introduction of nitrogen into the glass resulted in a decrease in activation energy, being reduced from 0,66 eV (for oxide glass) to 0,60 eV (for oxynitride glass). These results indicate a clear correlation between increased nitrogen content and enhanced electrical properties of the investigated glasses; although obtaining a homogeneous bulk glass after nitridation was not feasible. Therefore, the nitrided samples were pelletized and sintered under different thermal conditions to obtain characterizable samples. The findings suggest that nitrogen substitution could be a promising approach for enhancing the electrical properties of the glasses of the title system of composition. Further investigation is required to optimize the process and achieve homogeneous bulk oxynitride glass.

Forskningsområdet för bärbar elektronik är fortfarande relativt ungt och det finns ett stort behov av utveckling av nya material inom området. Olika typer av kompositer är mycket intressanta och de ska uppvisa såväl hög hållfasthet som goda ledande egenskaper. I detta avseende är silkes fibroin och MXene mycket intressanta utgångsmaterial eftersom silkestrådarna kan ge en struktur med god jonledningsförmåga och god flexibilitet och MXene kan bidra med hög styvhet och god elektrisk ledningsförmåga. Med detta som bakgrund beslöts att undersöka om kompositer av silkestrådar och MXene kan användas i kompositer som kan användas i bärbar elektronik. 3 olika typer av hydrogeler studerades och de innehöll silkes fibroin med 0, 1 och 5% MXene. De egenskaper som utvärderades var struktur, mekaniska egenskaper, stabilitet i vatten, bionedbrytbarhet och både statisk och dynamisk ledningsförmåga. Resultaten visar att de tillverkade nanokompositerna har lovande förutsättningar inom området eftersom en kombination av silkes fibroin med 5 % MXene har god stabilitet, konduktivitet och en hög och stabil Gauge-faktor. / As the research area of wearable electronics is still relatively new, material science with this focus opens plenty of unexplored fields. That is why a study characterizing the unexplored composite system of silk fibroin and MXene (Silk/MXene) was conducted. These two biocompatible materials are complementary with regard to the requirements for wearable electronics materials. Silk fibroin dispose an ionic conductivity and solid flexibility, while MXene brings mechanical strength and significant increase of electrical conductivity. The reinforced hydrogel materials were studied at two concentrations of fillers, 1% and 5% and compared to pristine silk fibroin. All three materials were studied from the point of view of their structure, mechanical properties, behaviour in aqueous environment, biodegradability and electrical conductivity, both static and dynamic. Nanocomposite systems of silk fibroin and MXene have shown a potential for being used in the intended application area, as Silk/MXene 5% film displays good stability, conductivity with high andstable Gauge factor.

Indiana University-Purdue University Indianapolis (IUPUI) / Several studies have found that resin-based amorphous calcium phosphate (ACP) composites can function well for applications that do not require high mechanical demand. Milled tricalcium phosphate (TCP), a new calcium-phosphate-releasing material, is crystalline in nature, suggesting it to be strong. In the present study, we investigated the use of a TCP-filled composite resin as a possible tooth restorative-material. An experimental TCP-based composite was prepared using monomer with a mixture of 34.3 percent by mass of EBPADMA, 34.2 percent by mass of HmDMA, and 30.5 percent by mass of HEMA. TCP fillers were added to the monomer mixture at different levels (30 percent, 40 percent, 50 percent, and 60 percent by weight). A universal testing machine (Sintech Renew 1121; Instron Engineering Corp., Canton, MA) was used to measure the compressive strength and modulus. FTIR was used to measure the degree of conversion. The depth of cure was determined according to the ISO standards for dental resin 4049 using the scrapping technique. Knoop hardness numbers were obtained by a microhardness tester (M-400; Leco Co., St. Joseph, MI). The viscosities of the experimental resin were determined in a viscometer (DV-II+ Viscometer; Brookfield, Middleboro, MA). The data were analyzed using a one-way analysis of variance (ANOVA). A 5-percent significance level was used for all the tests. Resin composites with 30-percent TCP filler showed the highest compressive strength and hardness values. Also, this group showed the lowest degree of conversion. Resin composites with 60-percent TCP filler showed the highest degree of conversion. However, this group showed the lowest compressive strength, depth of cure, and hardness. Resin composites with 50-percent filler showed the highest compressive modulus. Resin composites with 40-percent filler showed higher viscosity values than resin composites with 30-percent filler. In conclusion, increasing the filler level significantly reduced the compressive strength, hardness, and depth of cure, but increased the degree of conversion. Also, resin composites with the lowest filler level (30 percent) had the highest compressive strength, depth of cure, and hardness. From these results, it can be concluded that the experimental TCP-filled resin used in this study cannot be used as restorative material.

Indiana University-Purdue University Indianapolis (IUPUI) / Root canal therapy is a recommended treatment for apical periodontitis. Root canal failure can occur as a result of microbial leakage. Resilon, a resin based root canal obturating cone material introduced in 2004 attempts to minimize leakage by a unique bonding method of the resin sealer to both the core material and to the dentin of the canal walls. Resilon has no bactericidal or antimicrobial effect15. Furthermore, it has been shown that Resilon is susceptible to alkaline and enzymatic hydrolysis as well as bacterial degradation.73, 184-186 It has been suggested that Resilon may be susceptible to degradation by microorganisms found in the infected root canal space. This work focuses on the susceptibility of root canal obturating materials to be degraded by endodontic pathogens seen in root canal treated teeth with apical periodontitis. The aim of this study was to determine if Resilon could be degraded by selected pathogenic bacteria found in the infected root canal system, and if this degradation is more severe than with gutta-percha, a conventional obturating material. P. intermedia, E. faecalis and P. aeruginosa, known endodontic pathogens were inoculated on discs of obturating material (Resilon or gutta-percha) mounted on a platform and placed in wells containing TSB incubated at 37°C under aerobic conditions. The discs were polished, examined by SEM, profilometry, and elemental analysis prior to inoculation to establish a baseline, and were then re-examined by these methods one month after inoculation. The overall results were inconclusive; and using these methods it cannot be determined that the selected bacteria can degrade Resilon. An ideal future study would utilize SEM with gold coated samples as well as atomic force microscopy to evaluate for changes in topographical features of these obturating materials. A notable finding was that Resilon turns black when exposed to bacteria, and the significance of this finding should be addressed in future studies.

A study was conducted on sol-gel synthesis of an adsorbent (phosphotungstic acid embedded in silica gel, H-PTA/SiO­2) of radioactive cesium. A novelty of this work is covalent bonding of PTA to the surface of solid support that prevents leaching from the surface of the material. The sample was granulated with a binder, aluminium oxide (γ-Al2O3). Solid-state NMR and FT-IR spectroscopy were used to confirm the presence of Keggin units of PTA in the bound materials. Thermal analysis of H-PTA/SiO­2 - γ-Al2O3 (50 %) showed that the water content in the bound material was appreciably lower than in the pure adsorbent. Quantitative determination of surface acidity of porous materials is an important analytical problem in characterization of the adsorbents. This problem was solved by reversed titration after saturation of the materials by anhydrous solution of pyridine. Batch and column adsorption tests showed that the adsorbent demonstrated high adsorption capacities towards cesium.