<p>Multifunctional drug delivery systems incorporated with stimuli-sensitive drug release, magnetic nanoparticles and magnetic resonance (MR) <em>T</em>₂ contrast agents is attracting increasing attention recently. In this thesis, works on polymer nanospheres response to temperature change, superparamagnetic iron oxide nanoparticles (SPION)/polymeric composite materials for MR imaging contrast agents are summarized.</p><p>A “shell-in-shell” polymeric structure has been constructed through a “modified double-emulsion method”. Thermosensitive inner shell is comprised of poly(<em>N</em>-isopropylacrylamide) which undergoes phase transition at body temperature. Such a feature could facilitate drug release at an elevated temperature upon administration. Furthermore, the dual-shell structure is covered by a layer of gold nanoparticles. According to the cytotoxicity tests, the biocompatibility is shown to be enhanced due to the layer of gold.</p><p>SPION have been prepared using a high temperature decomposition method. Particle growth of SPION is monitored by transmission electron microscope and synchrotron X-ray diffraction. Poly(L,L-lactide)@SPION (PLLA@SPION) composite particles have been prepared through surface-initiated ring-opening polymerization which has been developed in our lab. For biomedical applications, it is essential to transfer the particles to physiological solutions from organic solutions. Phase transfer of SPION has been carried out by utilizing small molecules. Stability at the neutral pH is of large concern for such transfer systems. A novel phase transfer agent, Pluronic F127 (PF127), a triblock copolymer has been applied and the stability of the aqueous PF127@oleic acid (OA)@SPION solution has been greatly enhanced over a broad pH range. Most interestingly, PF127@OA@SPION show remarkable efficacy as T2 contrast agents as indicated by relaxometric measurements compared with commercially available products.</p>

Boric acid based fuel and oil additives were investigated in this study, with the aims to gain a deeper understanding of how the boric acid fuel additive behaves, to investigate the effect of low rates of fuel additive addition and tribofilm longevity, and to investigate how boric acid behaves as a hydraulic oil additive. Fuel additive experiments were performed in a reciprocating sliding rig with a cylinder on flat contact geometry with fuel additive sprayed on the contact repeatedly, whereas the hydraulic oil experiments were performed in a reciprocating sliding rig with a ball on flat contact with the oil and additive present from the start. Analysis was performed using vertical scanning interferometry (VSI), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The tribofilms created by the fuel additive provided excellent friction reduction capabilities, even with low or no rate of replenishment. As more additive was sprayed, wear resistance seemed to increase as the surface became increasingly covered. Film coverage need to be less than 20% of the surface in order to gain full friction reducing effects. The hydraulic oil additive had little effect on friction or wear resistance under the used parameters and no tribofilm was found.

Cu(In,Ga)Se2 (CIGS) is a semiconductor material and the basis of the promising thin-film photovoltaic technology with the same name. The CIGS film has a typical thickness of 1-2 mm, and solar cells based on CIGS technology has recently reached efficiencies of 23.3%. Ultra-thin CIGS solar cells use sub-micrometer thick films that require significantly less material and can be manufactured in a shorter amount oftime than films with typical thicknesses. With decreasing thickness, both electrical and optical losses get more significant and lower the overall performance. Electrical losses can be decreased by increasing the overall film quality and by utilising a graded bandgap throughout the CIGS layer. The band gap can be changed by varying the[Ga]/([Ga]+[In]) (GGI) ratio. Higher overall film quality and a higher band-gap towards the back of the absorber are expected to increase the performance. In this work, sputtered CIGS solar cells were made with different CIGS layer thicknesses, that ranged between 550-950 nm. Increased heat during deposition was examined and shown to increase the film quality and performance for all thicknesses. Two different ways of doping CIGS with Na was examined and it was found that higher Na content lead to an increasing predominance of the (112) plane. The bandgap was graded by varying the GGI composition throughout the CIGS layer and depth profiles were made with Glow-Discharge Optical Emission Spectroscopy (GDOES). It was found that a sputtered CuGaSe2 (CGS)layer below the CIGS-layer lead to a steep increase of the GGI near the back contact. When CGS made up 10% of the total CIGS layer thickness, a significant increase in performance was observed for all thicknesses. CIGS-absorbers with a less graded region with low GGI, making up 30% or 60% of the total CIGS layer thickness were made. A decrease in GGI in that region, was shown to increase the current but lower the voltage. No substantial increase in total performance compared to a fully graded CIGS layer was seen regardless of layer thickness. For further work the optical losses needs to be addressed and work on increasing the optical path in the CIGS layer needs to be done.

The electrolyte is a crucial part of any lithium battery, strongly affecting longevity and safety. It has to survive rather severe conditions, not the least at the electrode/electrolyte interfaces. Current commercial electrolytes based on 1 M LiPF 6 in a mixture of organic solvents balance the requirements on conductivity and electrochemical stability, but they are volatile and degrade when operated at temperatures above ca. 70°C. The salt could potentially be replaced with e.g. LiTFSI, but corrosion of the aluminium current collector is an issue. Replacing the graphite negative electrode by Li metal for large gains in energy density challenges the electrolyte further by exposing it to freshly deposited Li, leading to poor coulombic efficiency (CE) and consumption of both Li and electrolyte. Highly concentrated electrolytes (up to &gt; 4 M) have emerged as a possible remedy, by a changed solvation structure such that all solvent molecules are coordinated to cations – leading to a lowered volatility and melting point, an increased charge carrier density and electrochemical stability, but a higher viscosity and a lower ionic conductivity. Here two approaches to highly concentrated electrolytes are evaluated. First, LiTFSI and acetonitrile electrolytes with respect to increased electrochemical stability and in particular the passivating solid electrolyte interphase (SEI) on the anode is studied using electrochemical techniques and X-ray photoelectron spectroscopy. Second, lowering the liquidus temperature by high salt concentration is utilized to create an electrolyte solely of LiTFSI and ethylene carbonate, tested for application in Li metal batteries by characterizing the morphology of plated Li using scanning electron microscopy and the CE by galvanostatic polarization. While the first approach shows dramatic improvements, the inherent weaknesses cannot be completely avoided, the second approach provides some promising cycling results for Li metal based cells. This points towards further investigations of the SEI, and possibly long-term safe cycling of Li metal anodes. / Elektrolyten är en fundamental del av ett litiumbatteri som starkt påverkar livslängden och säkerheten. Den måste utstå svåra förhållanden, inte minst vid gränsytan mot elektroderna. Dagens kommersiella elektrolyter är baserade på 1 M LiPF 6 i en blandning av organiska lösningsmedel. De balanserar kraven på elektrokemisk stabilitet och jonledningsförmåga, men de är lättflyktiga och bryts ned när de används vid temperaturer över ca. 70°C. Saltet skulle kunna bytas ut mot t.ex. LiTFSI, vilket ökar värmetåligheten avsevärt, men istället uppstår problem med korrosion på den strömsamlare av aluminium som används för katoden. Genom att byta ut grafitanoden i ett Li-jonbatteri mot en folie av litiummetall kan man öka energitätheten, men då litium pläteras bildas ständigt nya Li-ytor som kan reagera med elektrolyten. Detta leder till en låg coulombisk effektivitet genom nedbrytning av både Li och elektrolyt. Högkoncentrerade elektrolyter har en mycket hög saltkoncentration, ofta över 4 M, och har lags fram som en möjlig lösning på många av de problem som plågar denna och nästa generations batterier. Dessa elektrolyter har en annorlunda lösningsstruktur, sådan att alla lösningsmedelsmolekyler koordinerar till katjoner – vilket leder till att de blir mindre lättflyktiga, får en ökad täthet av laddningsbärare, och en ökad elektrokemisk stabilitet. Samtidigt får de en högre viskositet och lägre jonledningsförmåga. Här har två angreppssätt för högkoncentrerade elektrolyter utvärderats. I det första har acetonitril, som har begränsad elektrokemisk stabilitet och ett högt ångtryck, blandats med LiTFSI för en uppsättning av elektrolyter med varierande koncentration. Dessa har testats i Li-jonbatterier och i synnerhet den passiverande ytan på grafitelektroder har undersökts med både röntgen-fotoelektronspektroskopi (XPS) och elektrokemiska metoder. En markant förbättring av den elektrokemiska stabiliteten observeras, men de inneboende bristerna hos elektrolyten kan inte kompenseras fullständigt, vilket skapar tvivel på hur väl detta kan fungera i en kommersiell cell. Med det andra angreppssättet har hög saltkoncentration nyttjats för sänka smältpunkten för en elektrolyt baserad på etylenkarbonat, som annars inte kan används som enda lösningsmedel. Dessa elektrolyter har testats för användning i Limetall-batterier genom långtidstest, mätning av den coulombiska effektiviteten och analys av deponerade Li-ytor med svepelektronmikroskop. Resultaten är lovande, med över 250 cykler på 0.5 mAh/cm2 och en effektivitet på över 94%, men framförallt observeras en mycket jämnare deponerad Li-yta, vilket kan möjliggöra säker cykling av Li-metall-batterier. Ett logiskt nästa steg är studier av Liytan med t.ex. XPS för att utröna vad som skiljer den från ytan som bildats i en 1 M referenselektrolyt.

EPDM and R-EPDM granules are used as infill on all of the artificial football fields in Uppsala. The aim of the study was to establish possible health risks related to the infill for players on artificial turf in Uppsala. Furthermore the aim was to investigate the possible ecotoxicological effect on surrounding waterways by the infill material. A comparative analysis concerning health and ecotoxicological effects for these materials was carried out. Eight different granules from the artificial turf in Uppsala was collected and analysed using TGA. The TGA results were modelled in two different scenarios to show possible air concentrations of 100-300 µg/m3 VOC over artificial football fields with EPDM granules. Calculations based on the tolerable daily dose of substances found in the granules were carried out. The conclusions of the study shows that the EPDM granules used today are safe from a health perspective. SBR granules from recycled tires does not constitute to any health risks either. The ecotoxicological risk for surrounding waterways is low. EPDM is less cost and energy efficient compared to SBR from recycled tires. Reduction of granular spill is very important from an environmental and cost point of view, regardless of the choice of material for artificial turf.

EPDM and R-EPDM granules are used as infill on all of the artificial football fields in Uppsala. The aim of the study was to establish possible health risks related to the infill for players on artificial turf in Uppsala. Furthermore the aim was to investigate the possible ecotoxicological effect on surrounding waterways by the infill material. A comparative analysis concerning health and ecotoxicological effects for these materials was carried out. Eight different granules from the artificial turf in Uppsala was collected and analysed using TGA. The TGA results were modelled in two different scenarios to show possible air concentrations of 100-300 µg/m3 VOC over artificial football fields with EPDM granules. Calculations based on the tolerable daily dose of substances found in the granules were carried out. The conclusions of the study shows that the EPDM granules used today are safe from a health perspective. SBR granules from recycled tires does not constitute to any health risks either. The ecotoxicological risk for surrounding waterways is low. EPDM is less cost and energy efficient compared to SBR from recycled tires. Reduction of granular spill is very important from an environmental and cost point of view, regardless of the choice of material for artificial turf.

Tablets are the most common forms of drug administration. They are convenient to administer and easy to manufacture. However, problems associated with the adhesion of the powders to the tableting tools are common. This phenomenon is known as sticking and even though it has been well documented and studied, it remains poorly understood. The many factors that contribute to good performance of the powders make the sticking problem difficult to solve. The goal of this study is to establish a relationship between the properties measured at the nanoscale to the overall tablet mechanical properties, tablet performance and powder pre-processing induced modifications. By using atomic force microscopy (AFM) we aim to develop an analytical method to characterize the mechanical and adhesive properties of the pharmaceutical powders at the nanoscale. Other methodologies such as scanning electron microscopy (SEM), thermal analyses (DSC, TGA) and tablet strength test were also used. The materials used in this study are commonly used excipients, a sticky drug and magnesium stearate (MgSt). Two different approaches offered by AFM were employed: sharp tip imaging and colloidal probe force measurements. Nano-mechanical properties of the materials were evaluated with a sharp tip cantilever showing that higher adhesion correlates with higher tablet cohesion and that both are significantly affected by the presence of MgSt. AFM characterization of the particle surface mechanical properties at the nanoscale was also used to detect the crystallinity and amorphicity levels of the materials. New approaches to presenting such data considering the particle heterogeneity and to track the dynamics of surface recrystallization are revealed. Adhesive interactions between a steel sphere and sticky and non-sticky powders were performed with the colloidal probe technique. Sticky materials presented a higher adhesion against the steel surface, and reveal the mechanism of stickiness. This work thus contributes to the provision of predictability of the performance of formulations at an early stage of the development process. / <p>QC 20170315</p>

The goal of this work was to evaluate the electrochemical properties of TiZrNbTa thin films deposited by magnetron sputtering using an industrial physical vapor deposition system. Samples were deposited on both Si(001) and 316L stainless steel. The samples deposited on Si(001) were either crystalline (bcc reflections) or amorphous, depending on the sputtering parameters. The crystalline films were composed of thin films with two different layers. The upper layer was nanocolumnar composed of elongated nanocolumns, while the lower was dense. The amorphous films had only one nanocolumnar layer and higher porosity. Polarization curves revealed that all samples had low corrosion current densities, in the order of 10-8 A/cm2. The samples showed an extended passive region up to 3.0 V vs Ag/AgCl due to the growth of a passivating oxide. The surface of the samples consisted of Nb2O5, ZrO2, TiO2 and Ta2O5. The chronoamperometry tests showed current oscillations, related to a break-down and reformation of the passive film. Electrochemical impedance spectroscopy revealed that all samples behaved similarly in all three electrolytes, and the simulated electrical circuits were indicating no corrosion reactions. A decrease in capacitance values after polarization was observed and was related to the formed surface oxide. Samples deposited on 316L stainless steel showed a passive regime for a shorter potential window, probably related to surface defects of the films. Heat treatments at 400 and 800 Celsius for 20 hours could not trigger the phase transformation from single bcc to hcp or dual bcc, as predicted by the Thermo-Calc software.

The near future will put a lot of demand on the increasing need for energy production and storage. Issues regarding the modern-day battery technology’s environmental benignity, safety and cost to sustain such demands thus serve as a huge bottleneck, necessitating the research into alternative electrochemical energy storage solutions. Conducting redox polymers are a class of materials which combines the concepts of conducting polymers and redox active molecules to work as fully organic electrode materials. In this work three conducting redox polymers based on 3,4-ethylenedioxythiopene and 3,4-propylenedioxythiopene (EPE) with hydroquinone, catechol and quinizarin pendant groups were investigated. The polymers were electrochemically characterized with regards to their ability to cycle protons (aqueous electrolyte) and cations (non-aqueous electrolyte), their kinetics and charge transport and as cathodes in a battery. In non-aqueous electrolyte, hydroquinone and catechol did not exhibit redox activity in a potential region where the backbone was conducting as they were not redoxmatched. Quinizarin showed redox-matching as concluded by in situ conductance and UV-vis measurements when cycling Na+, Li+, Ca2+ and Mg2+-ions in acetonitrile. Comparison of the kinetics revealed that the rate constant for Ca2+-ion cycling was several magnitudes larger than the rest, and galvanostatic charge/discharge showed that 90% of the polymer capacity was attainable at 5C. An EPE-Quinizarin cathode and metallic calcium anode coin cell assembly displayed output voltages of 2.4 V, and the presented material thus shows promising and exciting properties for future sustainable battery chemistries.

The layer-by-layer (LbL) technique was used to modify the surface of cellulose fibers by consecutive adsorption of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) followed by a final adsorbed layer of anionic paraffin wax colloids. Paper hand sheets made from the modified fibers were found to be highly hydrophobic with a contact angle of 150°. In addition to the significantly increased hydrophobicity, the sheets showed improved mechanical properties, such as a higher tensile strength. Heat treatment of the prepared sheets further enhanced both the mechanical properties and the hydrophobicity. These results demonstrate the flexibility and robustness of the LbL technique, which allows us to combine the known adhesive effect of PAH/PAA LbL films with the functionality of wax nanoparticles, creating a stronger and highly hydrophobic paper. It was further observed that LbL modified sheets without wax also displayed increased hydrophobicity when heat treated. The mechanism was studied through model experiments where LbL films of PAH/PAA were assembled on flat non-porous model cellulose surfaces. Contact angle measurements showed the same trend due to heat treatment of the model films, although, the absolute value of the contact angles were smaller. Analysis using the highly interfacial sensitive vibrational sum frequency spectroscopy technique showed an enrichment of CH3 groups (from the polymer chain ends) at the solid/air interface. These results indicate that during the heat treatment, a reorientation of polymer chains occurs to minimize the surface energy of the LbL film. In the second part of this work, the adhesive interactions between the main constituents of wood fibers were studied using high-resolution measuring techniques and well-defined model films of cellulose, hemicellulose and lignin. Successful surface modification of polydimethylsiloxane (PDMS) caps, needed in the Johnson-Kendall-Roberts (JKR) measuring methodology, by LbL deposition of nanofibrillated cellulose (NFC) and poly(ethylene imine) (PEI) allowed for the first known all-wood biopolymer JKR measurements of the adhesion between cellulose/cellulose, cellulose/lignin and the cellulose/glucomannan surfaces. The work of adhesion on loading and the adhesion hysteresis were similar for all three systems, suggesting that adhesion between the different wood biopolymers does not differ greatly. / <p>QC 20120314</p>