Electrospraying of polymer solutions for the generation of micro-particles, nano-structures, and granular films

S'ha realitzat un estudi sobre els mecanismes de formació de micropartícules polimèriques i les seves pel•lícules granulars, a partir de l'assecat de microgotes de electrosprays. L'estudi se centra en diferents solucions de tres polímers insolubles en aigua: polimetil(metacrilat), poliestirè, i etil cel•lulosa. L'assecat d'aquests electrosprays dóna lloc a diverses morfologies de partícula, que han estat determinades mitjançant microscòpia d'escombrat electrònic, i han estat caracteritzades en funció del solvent, concentració del polímer, el seu pes molecular, i la humitat relativa ambient. Les morfologies obtingudes inclouen una varietat d'estructures de partícula globulars i filamentoses, que, a humitat relativa elevada, poden desenvolupar porositat. Aquestes característiques morfològiques han estat explicades mitjançant models qualitatius que involucren fenòmens fluid dinàmics i sobre separació de fases, presents en sistemes relacionats amb els estudiats. Un dels fenòmens fluid dinàmics involucrats clau són les inestabilitats coulòmbiques de gotes elèctricament carregades. A més, la interacció de no solvent de l'aigua en la precipitació del polímer pot donar lloc a textures poroses sobre la superfície de les partícules. Les diferents formes de textura han estat explicades en referència als fenòmens de breath figure formation (BFF), i a la inversió de fases induïda per vapor (vapor induced phase separation, o VIPS). També hem estudiat el creixement de les pel•lícules granulars formades a partir de les partícules polimèriques. Demostrem que la càrrega elèctrica transportada per les partícules cap a la pel•lícula influeix fortament en la dinàmica de creixement d’aquesta. Un millor coneixement dels mecanismes estudiats en aquesta tesi hauria de permetre dissenyar nous processos de manufactura de partícules i recobriments basats en electrospray. Se ha realizado un estudio sobre los mecanismos de formación de micropartículas poliméricas y sus películas granulares, a partir del secado de microgotas de electropras. El estudio se centra en diferentes soluciones de tres polímeros insolubles en agua: polimetil(metacrilato), poliestireno, y etil celulosa. El secado de estos electrosprays da lugar a diversas morfologías de partícula, que han sido determinadas mediante microscopía de barrido electrónico, y han sido carSe ha realizado un estudio sobre los mecanismos de formación de micropartículas poliméricas y sus películas granulares, a partir del secado de microgotas de electropras. El estudio se centra en diferentes soluciones de tres polímeros insolubles en agua: polimetil(metacrilato), poliestireno, y etil celulosa. El secado de estos electrosprays da lugar a diversas morfologías de partícula, que han sido determinadas mediante microscopía de barrido electrónico, y han sido caracterizadas en función del solvente, concentración del polímero, su peso molecular, y la humedad relativa ambiente. Las morfologías obtenidas incluyen una variedad de estructuras de partícula globulares y filamentosas, que, a humedad relativa elevada, pueden desarrollar porosidad. Estas características morfológicas han sido explicadas mediante modelos cualitativos que involucran fenómenos fluido dinámicos y sobre separación de fases, presentes en sistemas relacionados con los estudiados. Uno de los fenómenos fluido dinámicos involucrados clave son las inestabilidades coulómbicas de gotas eléctricamente cargadas. Además, la interacción de no solvente del agua en la precipitación del polímero puede dar lugar a texturas porosas sobre la superficie de las partículas. Los diferentes tipos de texturas han sido explicadas en referencia a los fenómenos de breath figure formation (BFF), y a inversión de fases inducida por vapor (vapor induced phase separation, o VIPS). También hemos estudiado el crecimiento de las películas granulares formadas a partir de las partículas poliméricas. Demostramos que la carga eléctrica transportada por las partículas hacia la película influye fuertemente en la dinámica de crecimiento de ésta. Un mejor conocimiento de los mecanismos estudiados en esta tesis debería permitir diseñar nuevos procesos de manufactura de partículas y recubrimientos basados en electrospray.A study has been made of the mechanisms underlying the formation of polymeric microparticles and of their granular films, by drying of electrospray microdroplets. The study is focused on different solutions of three water-insoluble polymers: polymethyl(methacrylate), polystyrene, and ethyl cellulose. The drying of such electrosprays result in diverse particle morphologies, which have been determined by scanning electron microscopy, and have been characterized as a function of the solvent, polymer concentration, polymer molecular weight, and ambient relative humidity. The morphologies obtained include a variety of globular and filamented particle structures, which, at elevated relative humidity, can develop porosity. These morphological features have been explained using qualitative models involving fluid dynamic and phase separation phenomena which are known to occur in closely related systems. One of the key fluid dynamic phenomena involved is the coulombic instability of electrically charged droplets. In addition, the non-solvent interaction of water on the precipitation of the polymer can lead to porous textures on the particles surfaces. The different kinds of textures have been explained by reference to breath-figure formation (BFF) and vapor induced phase separation (VIPS) phenomena. We have also studied the growth of the granular films of such polymer particles. We show that the electrical charge transported by the particles to the film have a strong influence on the film growth dynamics. The better understanding of the mechanisms studied in this thesis, should help design new manufacturing processes of particles and coatings based on electrospray

FUNDAMENTAL IMPROVEMENT IN THE TRIBOCHARGING SEPARATION PROCESS FOR UPGRADING COAL

Triboelectrostatic separation is a physical separation technique that is based on surface electronic property differences among minerals to achieve a separation. Minerals have different surface conductivities and electron affinities. They are charged differently in quantity and/or polarity after a tribocharging process. Particles with different surface charges move discretely under external electric field produce a separation. Electrostatic separation is a dry mineral processing method that does not require any water or chemical reagents. It can greatly simplify the processing circuit and reduce operating cost. Additionally, problems caused by water in conventional wet mineral processing such as water freezing, dewatering, water pollution and water treatment are eliminated. Electrostatic separation has great potential as a fine particle separator (i.e. \u3c 1mm) in industrial minerals processing application, especially in arid areas where water supply is limited. In the current study, particle tribocharging kinetics was evaluated using a model system comprised of copper, pure coal, silica and ceramic. The results of the tribocharging process were recorded and analyzed using an oscilloscope and a signal processing technique. Charge exchange, charge separation and charge relaxation corresponding to tribocharging processes were studied using the generated pulsing signals. The signals provided a method to quantify the charge penetration into the conductor bulk during tribocharging. A new method to measure the particle surface charge using the pulsing was proposed and assessed, which was extremely useful for subtle surface charge measurements which effectively eliminated environmental noise. The interactive forces at the contacting interface, relative displacement, material electronic properties and ambient relative humidity were found to impact particle surface charge. The silica surface sites are 69 times more chargeable than the coal surface, which provides a fundamental explanation for upgrading that is achievable for silica-rich coal using triboelectrostatic separation. The influences of operating and environmental parameters were quantified and compared using an environment controlled chamber. Energy consumption at the interface was found to be positively correlated with the particle charge. Relative humidity has dual effects on the particle tribocharging, excessively low or high humidity levels do not favor particle tribocharging. Finally, a semi-empirical mathematical model of particle tribocharging was developed from the basic tribocharging compression model utilizing the parametric experiment study results. The model provides a more accurate method to predict particle surface charge under exact tribocharging conditions. A novel rotary triboelectrostatic separator (RTS) using the tribocharging mechanism was tested for upgrading fine coal. The particle size influencing the RTS tribocharging and separation process is investigated. A practical method to quantify the particle charging distribution was developed based on the direct particle charge measurement and a Gaussian distribution assumption. The smaller particles were found to have a higher average surface charge and wider surface charge distribution, which provided an opportunity to separate the high grade and the low grade coal particles. However, particles that are too small have weak particle-charger tribocharging effect that reduces particle tribocharging efficiency. The particle separation process was analyzed considering the exact experimental hydrodynamic separating conditions. Smaller particles were found to be more sensitive to the airflow that used to transport the particles as a result of the effect on residence time in the separation chamber. A method combining mathematical and statistical analysis was proposed to theoretically predict RTS separation efficiency based on the particle charging conditions and particle separation conditions. The particle horizontal displacement probability distribution was ultimately derived from this method. The model predictions indicate that a wider horizontal displacement distribution provides improved separation efficiency for the RTS unit. The theoretical analysis indicates that a particle size range between 0.105 and 0.21 mm has widest horizontal displacement distribution and thus represents an optimum particle size range which is in agreement with experimental results. The influences of the RTS operating parameters on separation performance achieved on a pure coal-silica mixture were investigated using a parametric study. The optimum operating conditions were identified. Using the optimum conditions, a five-stage separation process was conducted using the RTS unit to obtain the necessary data for the development of an ideal performance curve. Two stages of RTS separation were found to generate good quality clean coal with acceptable recovery. Particle tribocharging tests were performed using pure coal, pure silica and the coal-silica mixture as model feed materials. The test result found that mixing the pure coal with the sand reduced the particle charge distribution of the coal while increasing the charge distribution of the pure silica particle. The finding explains the inability to produce clean coal products containing ultra-low ash contents. However, the rejection of silica to the tailings stream is very high. The RTS upgrading of low-ash coal sample was tried using experiment design method, which revealed that feed rate was the most significant while the applied charger voltage and the injection air rate were the least significant in regards to product quality. Feed mass flow rate and the co-flow air rate have a significant interactive effect. Considering the theoretical findings, the impact of high feed rates is due to the negative effect on particle tribocharging efficiency resulting from an increase in the particle-particle surface charge relaxation. Under the optimum test conditions, an ultraclean coal was produced with an ash content of 3.85±0.08% with a combustible recovery of 62.97±1.11% using the RTS unit

Counterion and microcrystalline cellulose effects on the structural properties of starch at low moisture contents

Snacks are a rapidly growing sector of the food industry assisted by technological advances in the area of low-moisture materials. The major ingredient in snacks is starch, and different ingredients result in distinct physical properties of the final product including structure and expansion ratio during thermal processing. Along with starch type, increasing use of other ingredients particularly salts to achieve a variety of sensory profiles can have unexpected effects on the textural performance of commercial formulations. To date, molecular studies on these systems are scant in the literature, although the subject has important technological implications and affects the overall quality of preparations. This study examined the structural properties of condensed starch obtained from potato and cassava. Sample preparation included hot pressing at 120°C for 7 mins to produce extensive starch gelatinisation. Materials covered a range of moisture contents from 3.6 to 18.8%, which corresponded to relative humidity values of 11 and 75%. Salt addition in the form of sodium chloride and calcium chloride, with sodium and calcium ions being placed at opposite ends of Hofmeister series, was up to 6.0% in formulations. Instrumental work was carried out with dynamic mechanical analysis, modulated differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. Experimental conditions ensured the development of amorphous matrices thus imitating textural consistency in food products. It was found that moisture content variation affects dramatically the characteristics of the glass transition temperature (Tg) in potato starch. Sodium ions interact with the hydroxyl and phosphate groups of potato starch to alter considerably the mechanical properties of high-solid preparations. These become softer than starch-water systems at conditions of elevated temperatures governed by molecular mobility. In contrast, salt addition creates hard matrices at conditions of low temperature, which are characteristic of the mechanical glassy state. Densely packed salt-polysaccharide segments in the glassy state have a high energy requirement to molecular mobility that raises the Tg with increasing counterion content. Calcium is a stronger electrolyte than the sodium cation because of the dense electric charge. Dissolved calcium atoms in our systems, as opposed to crystallised calcium chloride, form specific electrostatic interactions with the polar and negatively charged sequences of the potato starch molecule inducing an antiplasticising effect on potato starch that stabilises the polymeric matrix in the glassy state. Strikingly, counterion effects were minimal in the non-phosphorylated amylopectin sequences of cassava starch, which exhibited similar structural behaviour with cassava starch-water samples. The final chapter deals with the effect of addition of microcrystalline cellulose (MCC), up to 6.0% w/w, on the physicochemical properties of potato starch based films. Composite materials were treated as for single starch systems to reveal that the inclusion of MCC increases the mechanical strength of the starch films. In contrast to salt addition, both moisture content and presence of MCC have a plasticising effect producing a reduction in the Tg. Overall, results indicate that there is no specific and non-trivial interaction between starch and MCC, with the elongated fibres acting as inert filler in the polymeric composite

Interfacial Phenomena in Pharmaceutical Low Moisture Content Powder Processing

Powders are essential materials in the pharmaceutical industry, being involved in majority of all drug manufacturing. Powder flow and particle size are central particle properties addressed by means of particle engineering. The aim of the thesis was to gain knowledge on powder processing with restricted liquid addition, with a primary focus on particle coating and early granule growth. Furthermore, characterisation of this kind of processes was performed. A thin coating layer of hydroxypropyl methylcellulose was applied on individual particles of ibuprofen in a fluidised bed top-spray process. The polymeric coating improved the flow properties of the powder. The improvement was strongly related to relative humidity, which can be seen as an indicator of a change in surface hydrophilicity caused by the coating. The ibuprofen used in the present study had a d50 of 40 μm and thus belongs to the Geldart group C powders, which can be considered as challenging materials in top-spray coating processes. Ibuprofen was similarly coated using a novel ultrasound-assisted coating method. The results were in line with those obtained from powders coated in the fluidised bed process mentioned above. It was found that the ultrasound-assisted method was capable of coating single particles with a simple and robust setup. Granule growth in a fluidised bed process was inhibited by feeding the liquid in pulses. The results showed that the length of the pulsing cycles is of importance, and can be used to adjust granule growth. Moreover, pulsed liquid feed was found to be of greater significance to granule growth in high inlet air relative humidity. Liquid feed pulsing can thus be used as a tool in particle size targeting in fluidised bed processes and in compensating for changes in relative humidity of the inlet air. The nozzle function of a two-fluid external mixing pneumatic nozzle, typical for small scale pharmaceutical fluidised bed processes, was studied in situ in an ongoing fluidised bed process with particle tracking velocimetry. It was found that the liquid droplets undergo coalescence as they proceed away from the nozzle head. The coalescence was expected to increase droplet speed, which was confirmed in the study. The spray turbulence was studied, and the results showed turbulence caused by the event of atomisation and by the oppositely directed fluidising air. It was concluded that particle tracking velocimetry is a suitable tool for in situ spray characterisation. The light transmission through dense particulate systems was found to carry information on particle size and packing density as expected based on the theory of light scattering by solids. It was possible to differentiate binary blends consisting of components with differences in optical properties. Light transmission showed potential as a rapid, simple and inexpensive tool in characterisation of particulate systems giving information on changes in particle systems, which could be utilised in basic process diagnostics.Jauheet ovat tärkeä materiaali lääketeollisuudessa, sillä jauheita tavataan laajalti monissa lääkkeenvalmistusprosesseissa. Jauheen valumisominaisuudet ja hiukkaskoko ovat keskeisiä ominaisuuksia, joita pyritään muokkaamaan jauheteknologian keinoin. Tämän väitöstyön tavoitteena oli tutkia kuinka jauheita voi muokata rajoittamalla prosessiin lisättävän nesteen määrää. Pääasiallinen mielenkiinto kohdistui hiukkasten pinnan päällystämiseen ja rakeen varhaiseen kasvuun. Lisäksi tutkittiin menetelmiä, joiden avulla yllämainitun kaltaisia prosesseja voidaan karakterisoida. Ibuprofeenijauheen yksittäisten hiukkasten pinta päällystettiin polymeeripäällysteellä leijukerrosrakeistimessa. Kyseinen päällyste paransi jauheen valumisominaisuuksia. Muutos oli vahvasti riippuvainen ilmankosteudesta. Tämän voi tulkita osoituksena päällysteen aiheuttamasta pinnan hydrofilisuuden muutoksesta. Tutkimuksessa käytetyn ibuprofeenijauheen mediaanihiukkaskoko oli n. 40 µm ja se määritellään Geldart jauheenluokitusjärjestelmässä luokkaan C, eli jauhe luokitellaan haastavaksi materiaaliksi kuvaillunkaltaisissa leijukerrosprosesseissa. Ibuprofeenijauhetta päällystettiin myös uudella ultra-ääneen perustuvalla menetelmällä. Tulokset olivat johdonmukaisia yllämainitun leijukerrosprosessin tulosten kanssa. Todettiin että ultraääniavusteinen menetelmä on helppokäyttöinen ja varma menetelmä yksittäisten hiukkasten päällystämiseksi. Rakeen kasvua leijukerrosrakeistimessa rajoitettiin syöttämällä rakeistusneste pulssittain. Tulokset osoittavat että pulssitussyklin pituus on olennainen muuttuja rakeen kasvun säätelemiseksi. Lisäksi havaittiin pulssittaisen nesteensyötön vaikutuksen rakeen kasvuun korostuvan korkeassa suhteellisessa ilmankosteudessa. Pulssittaista nesteensyöttöä voi näin ollen käyttää hiukkaskoon säätelyyn, minkä lisäksi sillä voidaan kompensoida tuloilman ilmankosteuden vaihtelun aiheuttamia vaikutuksia prosessiin. Rakeistimissa yleisesti käytetyn nestesumuttimen toimintaa osana prosessia tutkittiin huippunopealla kameralla ja pisarantunnistusohjelmistolla. Pisaroiden todettiin yhdistyvän niiden liikkuessa suuttimesta poispäin. Pisaroiden yhdistymisen todettiin lisäävän niiden nopeutta. Nestesumun pyörteisyyttä tutkittaessa havaittiin pisaranmuodostuksen ja vastakkaiseen suuntaan liikkuvan ilmavirran aiheuttama pyörteisyys. Tulokset osoittivat että kyseinen menetelmä soveltuu nestesumun karakterisoimiseen osana prosessia. Hiukkaspedin läpi kulkevan valon, eli valotransmission, todettiin sisältävän informaatiota hiukkaskoosta ja hiukkasten pakkautumistiheydestä. Tutkimalla transmittoituvaa valoa oli mahdollista erottaa koostumukseltaan poikkeavia kahden komponentin seoksia. Valotransmissio todettiin nopeaksi, yksinkertaiseksi ja kustannustasoltaan alhaiseksi menetelmäksi karakterisoida hiukkassysteemejä. Parhaiten menetelmää voisi hyödyntää prosessiseurannassa hiukkassysteemeissä tapahtuvien muutosten havaitsemiseksi

Synthetic modifications of metal organic framework adsorbents for environmental remediation

The widespread usage of organic chemicals has led to an unprecedented level of pollution and associated health risk concerns. Although activated carbon (AC) based adsorption is commonly used in wastewater treatment and air purification processes, now, new metal-organic frameworks (MOFs) adsorbents with superior surface areas, chemically tuneable structures, and excellent reusability are available. This thesis evaluates the application of selected MOFs and their modified variants for removing organic pollutants from aqueous and humid air streams, reporting adsorption capacity and kinetics. For the removal of aqueous phase pollutant 2-chlorophenol, the higher surface area of MIL-101 (Cr) even with improved surface amination, gave inferior adsorption capacity compared to the hydrophobic AC, indicating the importance of MOF’s hydrophobicity. A hydrophobic MIL-101 (Cr) was synthesized using a PDMS vapour coating protocol, creating a new material with the same surface area and pore volume as pristine MIL-101 (Cr). For 0.5% toluene P/P0 vapour co-adsorption at 40% RH, this composite showed a 60% higher uptake capacity and a 34% higher aggregate adsorption rate compared to pristine MIL-101 (Cr), and 360% faster kinetics relative to AC. A solution-based treatment for MIL-100 (Fe) was developed using calixarene, producing super hydrophobic surfaces, which at 40% RH and 0.5% toluene P/P0, exhibited a 68% higher aggregate uptake rate, despite having lower pore volumes and surface areas. Finally, MIL-96 (Al) was modified using hydrolysed polyacrylamide polymer, which enlarged the 3.2-µm particles by 225% and transformed their crystal morphology. The polymer also contains amide with NH2 moieties which improved the modified MIL-96 (Al)’s uptake capacity of perfluorooctanoic acid. Overall, this thesis highlights the complexity of co-adsorption when hydrophobic and hydrophilic adsorbates are both present. It also recalls the importance of adsorption kinetics, in contrast with current MOF research emphases, which are on surface area and adsorption capacity. Faster adsorption kinetics may be preferred over a slow-diffusing adsorbate, even if the final uptake capacity is superior, for some industrial applications.Open Acces

Wet spinning fibres from imogolite and carbon nanotubes

As 1D materials with high intrinsic strength and stiffness, nanotubes are promising building blocks for the next generation of fibres in structural composites. This thesis explores wet spinning techniques for assembling macroscale fibres from nanotubes. Carbon nanotubes (CNTs) are an obvious target material to compete with commercial carbon fibres, based on their excellent intrinsic mechanical properties and low density, alongside high electrical conductivity for multifunctional applications. However, studying CNT materials is challenging due to their intrinsically high optical absorbance and low X-ray scattering cross-section, as well as the dispersity of typical feedstocks in both size and helicity. Imogolite nanotubes (INTs) are an inorganic analogue that offers an opportunity to observe the assembly of nanotubes into fibres using both polarised optical microscopy (POM) and X-ray scattering (XRS). In contrast to CNTs, INTs are optically transparent and can be synthesised at low temperature to provide feedstocks that are uniform in structure and diameter. In this work, the first known pure INT fibres have been produced and used to understand the nanotube wet spinning process. In situ POM demonstrated that in cylindrical spinnerets the spinning dope undergoes plug flow with inhomogeneous alignment due to the shear thinning nature of the solutions. The use of a tapered spinneret enables good alignment of the spinning dope, due to the induced extensional flow. Using this information, CNT fibres were spun from reduced CNT solutions and the wet spinning process was refined using a combination of in situ observation and statistical experimental design. The dissolution of negatively-charged CNTs (nanotubides) was examined both from a theoretical perspective and experimentally to identify the key conditions required to obtain homogeneous spinning dopes. The optimal dissolution depended upon both degree of charging and effective stirring. The optimised CNT dope was then wet spun using a variety of coagulating systems to identify the accessible process window and optimum parameters for spinning from these reactive charged solutions. Further improvement of the CNT fibre properties is predicted to arise through the use of higher aspect ratio CNT feedstocks. However, challenges still remain in the liquid phase processing of longer CNTs. In order to create CNT fibres competitive with commercial CFs, future research should focus on how to process these longer feedstocks following the guidance in this thesis.Open Acces

Optimization and Longevity of Functionalized Multi-Walled Carbon Nanotube-Enabled Membranes for Water Treatment

Water scarcity is a growing concern at the global scale. Large scale water reuse is growing both in necessity and popularity. Before water reuse can be performed efficiently on a large scale or be used for potable supply, even indirectly, contaminants of emerging concern (CECs) will need to be treated at the full scale. Advanced oxidation processes (AOPs) are a form of advanced water treatment capable of treating a wide range of CECs. This study contributes to the growing field of AOPs and more specifically AOPs using ozone combined with functionalized multi-walled carbon nanotubes (MWCNTs). Ozonation of MWCNTs has been found to increase hydroxyl radical production and improve AOP treatment. Novel MWCNT-enabled membranes were used as catalysts for ozonation to degrade the CEC Atrazine. Atrazine is an ozone recalcitrant CEC that is commonly found in herbicides. Atrazine removal results, found using a high-performance liquid chromatograph (HPLC), were inconsistent between membranes constructed using identical procedures. Further analysis using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopes (SEM), and UV-Vis spectrophotometry was conducted to explore inconsistencies in construction of the membranes which might explain removal inconsistencies and predict membrane longevity. Removal was found to be influenced by filtration time and ozone exposure. Ozone exposure and filtration time influence percent removal because they both affect hydroxyl formation. The membrane test filtration duration, for equal filtered volumes, ranged from under 5 minutes to nearly an hour. It is believed that filtration time inconsistency was due to inconsistent MWCNT loading on the surface of the membranes. Extended exposure to ozone might change the surface chemistry of the MWCNTs on the membrane surface, affecting hydroxyl radical production. Additionally, repeated use of the membrane created surface defects that might reduce the membrane strength. This study found that the lifetime of the membrane is far past what was simulated in lab and further testing must be performed

Improved Sample Loading for Plutonium Analysis by Thermal Ionization Mass Spectrometry and Alpha Spectroscopy

Thermal ionization mass spectrometry (TIMS) and alpha spectroscopy are powerful analytical techniques for the detection and characterization of Pu samples. These techniques are important for efforts in environmental monitoring, nuclear safeguards, and nuclear forensics. Measurement sensitivity and accuracy are imperative for these efforts. TIMS is internationally recognized as the “gold standard†for Pu isotopic analysis. Detection of ultra-trace quantities of Pu, on the order of femtograms, is possible with TIMS. Alpha spectroscopy has a long history of use in the detection and isotopic analysis of actinides and can be a simpler and less expensive alternative to mass spectrometer based techniques. The sensitivity and accuracy of both techniques is highly dependent upon the method of sample loading. High quality sample loading is often tedious, time consuming, and expensive. In this work, we sought to simplify and improve high quality sample loading for TIMS in an effort to expand the utility and improve the sensitivity of this technique. During these efforts a promising sample loading method for alpha spectroscopy was developed. Three improvements were developed for sample loading procedures for isotope ratio measurements of ultra-trace quantities of Pu using (TIMS). Firstly, a new filament geometry, the “dimpleâ€, was developed. The bead loading method was used for these analyses. Beads were loaded with New Brunswick Laboratory certified reference material (NBL CRM) Pu128 (239Pu and 242Pu) from an 8M HNO3 matrix. Overall ion counts and isotopic ratios measured using the dimpled filament geometry were compared to those measured when using the established V-shaped filament geometry. The average number of Pu counts detected when using dimpled filaments was approximately 34% greater than ion counts detected using V-shaped filaments. The accuracy and precision of isotopic ratio measurements were unaffected by the use of dimpled filaments. The well-like geometry of dimpled filaments aids in sample loading and alignment. Additionally, the use of dimpled filaments was found to reduce sample losses inside the ion source. Over the course of 25 measurements, no sample losses were experienced on dimpled filaments, in contrast to 15% total sample loss experienced with v-shaped filaments. Secondly, a polymer fiber architecture for TIMS sample loading was developed using similar sample loading procedures as those used in bead loading. Fibers with diameter of approximately 100 μm were prepared from triethylamine-quaternized-poly(vinylbenzyl chloride) cross-linked with diazabicyclo[2.2.2]octane. Total ion counts (239Pu + 242Pu) and isotope ratios obtained from fiber-loaded filaments were compared to those measured bead loading. Fiber loading was found to improve sensitivity, accuracy, and precision of isotope ratio measurements of Pu compared to the established resin bead loading method, while maintaining its simplicity. The average number of detected Pu+ counts was 180% greater and there was a 72% reduction in standard deviation of ratio measurements when using fiber loading. An average deviation of 0.0003 (0.033%) from the certified isotope ratio value of NBL CRM Pu128 was measured when fiber loading versus a deviation of 0.0013 (0.133%) when bead loading. The fiber formation method can be extended to other anion-exchange polymer chemistries, and therefore offers a convenient platform to investigate the efficacy of novel polymer chemistries in sample loading for TIMS. Thirdly, a sample loading procedure was developed that is based on a polymer thin film architecture. Rhenium filaments were degassed, dip-coated with a thin (~180 nm) hydrophobic base layer of poly(vinylbenzyl chloride) (PVBC), and spotted with an aqueous solution of triethylamine-quaternized-PVBC and a cross-liking agent (diazabicyclo[2.2.2]octane). Spotting resulted in the formation of a toroidal, hydrophilic extractive polymer disk surrounded by the hydrophobic base polymer. Thin film coated filaments were direct loaded with NBL CRM Pu128 from a 9 M HCl matrix. Aqueous sample droplets adhered to the extractive polymer spot, facilitating sample loading. The influence of spot thickness upon ion production was investigated. Overall ion counts and isotopic ratios obtained from thin film coated filaments were compared to those produced by the established resin bead loading method. Isotopic ratios were within error of those measured using the bead loading method with few background interferences. The average number of detected Pu+ counts was 175% greater when using thin film coated filaments with 20-30 μm thick toroidal spots. The use of dimpled filaments further aided sample loading by providing a well-shaped substrate to deposit the sample droplet. No sample loss was experienced with the thin film loading method over the course of 65 sample analyses. Finally, thin films used in this design were found to slow filament aging under atmospheric conditions, facilitating the bulk production of filaments for future analyses. During this work, an unreported form of rhenium surface oxidation was discovered. Rhenium is the most common ionization filament material for Pu analysis by TIMS. Degassing is a common preparation technique for rhenium filaments and is performed to clean filaments before analysis. Degassing involves resistively heating the filaments under high vacuum to volatilize and degrade contaminants. Collaborators at Savannah River National Laboratory reported anecdotally that the use of excessively aged filaments (on the order of 2 months of aging in atmosphere after degassing) decreased the sensitivity and precision of TIMS analyses. Although optimization studies regarding degassing conditions have been reported, little work has been done to characterize filament aging after degassing. In this study, the effects of filament aging after degassing were explored to determine a “shelf-life†for degassed rhenium filaments, and methods to limit filament aging were investigated. Zone-refined rhenium filaments were degassed by resistance heating under high vacuum before exposure to ambient atmosphere for up to 2 months. After degassing, the nucleation and preferential growth of oxo-rhenium crystallites on the surface of polycrystalline rhenium filaments was observed by atomic force microscopy and scanning electron microscopy (SEM). Compositional analysis of the crystallites was conducted using SEM-Raman spectroscopy and SEM energy dispersive X-ray spectroscopy, and grain orientation at the metal surface was investigated by electron back-scatter diffraction mapping. Spectra collected by SEM-Raman suggest crystallites are composed primarily of perrhenic acid. The relative extent of growth and crystallite morphology were found to be grain dependent and affected by the dissolution of carbon into filaments during annealing (often referred to as carbonization or carburization). Crystallites were observed to nucleate in region specific modes and grow over time through transfer of material from the surface. The roles of atmospheric humidity and carburization on the oxidation characteristics (i.e. aging) of rhenium filaments were studied. Degassed and carburized filaments were aged for up to 79 days under dry and humid conditions, and the growth of oxo-rhenium crystallites was investigated intermittently by SEM to construct growth profiles. SEM images were analyzed to determine average crystallite size, number density, and percent surface coverage. Crystallite growth was found to be suppressed by both filament carburization and dry storage conditions (~13% relative humidity). Under humid conditions (75% relative humidity), crystallite growth progressed steadily over the investigatory period, reaching \u3e2.3% surface coverage within 79 days of aging. Atomic ion production of Pu+ was suppressed by approximately 20% and the standard deviation of isotope ratio measurements was increased by 170% when filaments with 1% oxide surface coverage were used in sample loading. Measurement sensitivity and reproducibility are imperative for applications involving ultra-trace analysis of Pu by TIMS. These findings offer validation for observations regarding the detrimental effect of excessive filament aging post-degassing, improve the understanding of conditions that impel the oxidation of rhenium filaments, and provide practical means to suppress the growth of oxides. PVBC nanolayers were found to slow the growth of oxo-rhenium crystallites on the filament surfaces and may serve as an alternative carbon source for filament carburization. A novel substrate for the simultaneous concentration of actinides and sample preparation for alpha spectroscopy was developed using thin films originally intended for TIMS sample loading. Substrate preparation involved forming ultrathin films (10-180 nm) of quaternary amine anion-exchange polymers on glass and silicon by dip-coating. Samples were loaded by submerging the polymer-coated substrates into acidified solutions of Pu or natural water with elevated uranium concentrations. High resolution (25-30 keV) alpha spectra were acquired from these substrates under certain loading conditions indicating that through further development they may be a useful, inexpensive, and potentially field deployable platform serving national security and environmental sampling applications