Ionic liquids are continuously finding more and more applications, both in research and in the industry. Many attempts have been made to find parameters that could be used to describe all ionic liquid systems. Five years ago a Japanese group applied the work of Gutmann on ionic liquids to use ionic association to describe solvation effects. The group calculated ionic association from conductivity and diffusion measurements. This report presents a direct approach through electrophoretic NMR to measure ionic association in ionic liquids.  The report contains a brief introduction to ionic liquids and their properties as well as a short explanation of Nuclear Magnetic Resonance (NMR) spectroscopy, diffusion NMR and a more detailed explanation of electrophoretic NMR (eNMR). Experimental setups, taken from previous work by the NMR group at Physical Chemistry KTH, have been modified to allow for measurements in ionic liquid systems. The report discusses the issues that can arise when measuring eNMR in ionic liquids and suggests solutions. The method developed is principally built upon experiments on 1-butyl-3-methyl-imidazolium trifluoroacetate and is directly applicable to other ionic liquid systems. For more viscous systems than the one investigated here, slight changes will need to be made, as explained in the report.  In order to evaluate the method developed during the project the degree of association for 1-butyl-3-methyl-imidazolium trifluoroacetate has been calculated from experimental results and results in similar values as reported by Tokuda et al.. Furthermore, the temperature variation due to Joule heating during a complete eNMR experiment was also investigated by observing change in chemical shift.

This thesis has been focused around the Diels Alder reaction with the goal to design an enzyme catalyzed reaction pathway. To achieve this goal computer aided enzyme design was utilized. Common traditional methods of computational chemistry (B3LYP, MP2) do not do well when calculating reaction barriers or even reaction energies for the Diels Alder reaction. New calcu- lation methods were developed and tested. This was the focus of the first part of the thesis, by choosing a small system, extensive and heavy calculations could be done with CBS-QB3. Then by benchmarking faster methods of calculation (SCS-MP2, M06-2X) against the results, they could be graded by efficiency and cost. This was done anticipating that the same accuracy could be applied to larger systems where CBS-QB3 cannot be used. In the second part activating groups were investigated for both the diene and the dienophile, along with their effects on reaction rates. A qualitative analysis was done. This is important not only for the uncatalyzed reaction, but also interesting when searching for possible substrates for the enzyme reaction. In the last part the thesis presents a designed enzyme that catalyzes Diels Alder in silico using ∆5−3−Keto steroid isomerase. Using empirical calculations, the enzyme was scanned for catalytic activity. The catalytic effect was then showed with ab initio Quantum chemical calculations.

Electrochemical quartz crystal microbalance has been employed to investigate electro-responsiveness of an ionic liquid as an additive in lubricant oils on a gold surface. Polarisation of the surface reveals changes in frequency where an increase in magnitude amplified the observed response, corresponding to a controllable alternation of the ionic liquid configuration on the surface as a function of applied potential. The frequency changes are due to different packing of the anion and cation, respectively, on the surface as their mass densities and geometries are different. Relaxation of the system was reversible to the application of a potential and it was also found to be diffusion dependent, where the ratio between the ion diffusivities could be extracted from the results. Measurement of the system relaxation reveals a potential decay of that of a discharging capacitor, with an internal resistance inducing an initial potential drop due to the resistivity of the oil medium. The discharge behaviour was also proven to show high internal reproducibility validity within experiments. This newly discovered insight in responsive differences of ion packing is of importance, not only for ionic liquid additives in tribology, but for understanding and exploiting ionic liquids in an array of electrochemical applications.

The liquid-liquid phase separation (LLPS) of biomolecules is a phenomenon which received a lot of attention in the last years because it is not only related to theformation of membraneless organelles but also to neurodegenerative diseases. Lysozyme is a globular protein that undergoes LLPS in a buffer salt system andfor that it is well investigated with several techniques like microscopy, dynamic lightscattering (DLS) or small-angle X-ray scattering. In this work we investigate the effect of temperature, solvent and sample con-centration on the diffusion coefficient, the hydrodynamic radius and the viscosity oflysozyme using a DLS setup. Furthermore, the influence of these parameters on thecluster formation is addressed. Finally, we investigate the question if the LLPS oflysozyme in a buffer environment effects the formation of dynamic clusters.

Detergents are broadly used in our everyday life for cleaning and washing procedures. They are however, a source of water pollution and can have a negative effect on human health and the environment. To reduce their negative impact, a new trend of using only pure water for washing and cleaning applications is being implemented. However, a scientific basis needs to be established first, as the mechanisms and the effectiveness of this method are not fully understood. In this work, we aim to investigate the effect of water purity on the removal of oil from surfaces and the stability of colloidal systems. To do that, two purified water grades are compared with non-purified tap water and 10 mM NaCl solution. Results from measurement of oil film mass before and after water contact and Quartz Crystal Microbalance with Dissipation (QCM-D) indicate that purified water grades can wash a surface more efficiently than non-purified water grades. Contact angle measurements show that pure water facilitates the cleaning process while spreading of oil on plastic surfaces indicates that electrostatic interactions have an important role in the system. Visual observations of o/w emulsions, show that purified water grades redisperse the oil better. We hypothesize that the mechanism behind the cleaning and washing without detergents relies on the electrostatic interactions. To further investigate the effect of salt on cleaning mechanisms, we performed zeta potential measurements. Results indicate that salt has a negative effect on the stability of the particles.

Since our society became industrialised, the levels of carbon dioxide in our atmosphere have been steadily rising, to the point where it in early 2020 at is 413 ppm. The high concentration is causing several troubling effects worldwide because of the increase in mean temperature that it creates, which causes longer draughts, more severe floods, and rising seawater levels to name a few. There are a few measures that can be taken to reduce carbon dioxide in the atmosphere, among which there are a number of methods that currently are being researched and/or used. The prospect of capturing carbon dioxide and using it as a carbon building block to make methanol is one solution that is particularly interesting, since it in theory could provide a fuel for combustion engines that is net neutral regarding carbon emission. Methanol can be synthesised from carbon dioxide using a heterogeneous catalyst consisting of copper, Cu, and zinc oxide, ZnO. This research is focused on one of the components of the catalyst, the metal oxide ZnO in the form of crystallites or nanoparticles (ZnO)n. Quantum chemistry is a branch of computational chemistry which is centered on solving the Schrödinger equation for molecular systems. Density functional theory, DFT, is an approach to quantum theory which in this study was used to calculate the geometry and energy of the particles. The supercomputer Tetralith in the National Supercomputer Centre, NSC, was used to carry out the calculations. The DFT calculations utilized the functional B3LYP and the basis set 6-31G (d,p). One of the largest particle sizes studied, (ZnO)20, with a structure that has a large, flat surface, was found to be the most energetically favourable. According to studies, the presence of an oxygen vacancy on the surface of ZnO reduces the amount of activation energy required for CO2 to bond to the particle, which increases the chance of forming CO and thus continuing the process of forming methanol. Two structures of (ZnO)20 were investigated in this regard, where oxygen atoms were removed at different locations, creating four versions of Zn20O19 in total. This proved yet again that the version with a large, flat surface yields the lesser amount of energy when an O atom is removed from the centre of its surface. The adsorption of CO2 to the ZnO clusters was studied by calculating the energy of adsorption, and this showed that it was the second version of (ZnO)20, without an O vacancy, that yielded the least amount of energy, thus being the most favourable species to engage in physisorption with CO2. Lastly, the activation energy was investigated, and a diagram of the reaction process of CO2 adsorbing to Zn20O19 forming (ZnO)20 and CO is presented in this paper, which shows that the required activation energy is 127 kJ/mol.

Interphase phenomenon gains more and more interest throughout the research community. An interphase is formed between a filler particle and a polymeric matrix, and it may constitute almost the entire volume of a nanocomposite. If the interphase have favorable mechanical properties it will thus result in a nanocomposite with such properties. Therefore, understanding the principles of its formation and properties are crucial in order to design advanced nanocomposites. This thesis focuses on PDMS-carboxylic acid modified latex nanoparticles (PDMS-CML) surface composites investigated by means of Atomic Force Microscopy (AFM). A new sample preparation method was designed and utilized together with the Gel Trapping Technique (GTT). Quantitative Imaging Mode and Contact Mode were utilized in the AFM studies. Topography and nanomechanical properties were investigated and compared for pure PDMS and PDMS containing the nanoparticles. Further, Contact Mode was used to investigate nanoscale wear of the samples in order to elucidate the interactions strength between the nanoparticles and the matrix. / Egenskaper hos interfaser är ett område som röner allt större intresse hos forskarna inom materialområdet. En interfas bildas mellan en fillerpartikel och en polymermatris, och den kan utgöra den största volymen i en nanokomposit. Ifall interfasen har fördelaktiga mekaniska egenskaper så resulterar det alltså i att nanokompositen också får det. Det är därför viktigt att först principerna för hur interfasen bildas och får sina egenskaper om man vill framställa avancerade nanokompositer. I det här avhandlingsarbetet lades fokus på PDMS och karboxylsyrefunktionaliserade latex nanopartiklar som bildade en nanokomposit yta, vilken studerades med atomkraftsmikroskopi (AFM). En ny framställningsmetod togs fram och utnyttjades tillsammans med den så kallade ”Gel Trapping” tekniken (GTT). Quantitative Imaging och kontakt mode utnyttjades vid AFM studierna. Topografin och de nanomekaniska egenskaperna studerades för ren PDMS och PDMS blandat med nanopartiklarna. Nötning på nanometernivå studerades också, och dä med AFM i kontakt mode.

Semiconductor colloidal quantum dots have an interesting potential to increase solar cell efficiency, with strong absorption in the infrared region and a tunable band gap. In this work an attempt was made to adopt a manufacturing process for PbS quantum dot solar cells, proven successful at Uppsala University. Two optimizations were investigated and the stability of the quantum dot films was analyzed with regards to three storage conditions, varying oxygen accessibility and light exposure, and measured with UV-Vis spectroscopy and X-ray photoelectron spectroscopy. Functioning solar cells were obtained but with lower performance than the results from Uppsala. Optimizations were partly successful with regards to improved spreading of the EDT solution on the PbS quantum dot film using ethanol and methanol as solvents. No improved cell performance was observed by applying both QD films inside argon atmosphere, as opposed to only the first one. Clear differences in oxidization of the films and loss of iodine ligand could be identified for the different storage conditions, with best stability exhibited by films stored under argon atmosphere. / Kvantprickar av halvledande material har en intressant potential att förbättra solcellers verkningsgrad genom en stark absorption inom de infraröda spektrat och ett justerbart bandgap. I detta arbete gjordes ett försök att återskapa en tillverkningsprocess av kvantprickssolceller av PbS, som visat sig framgångsrik vid Uppsala universitet. Två optimeringar undersöktes och stabiliteten av kvantpricksfilmerna analyserades med avseende på tre förvaringsmiljöer med olika exponering för ljus och syre, och mättes med UV-visspektroskopi samt röntgenfotoelektronspektroskopi. Fullt fungerande solceller framställdes men med en lägre prestanda jämfört med resultaten i Uppsala. Optimeringarna var delvis lyckade gällande spridning av EDTlösningen på kvantpricksfilmen av PbS genom att använda etanol och metanol som lösningsmedel. Ingen förbättrad prestanda observerades hos cellerna genom att applicera båda kvantpricksfilmerna i argonatmosfär, jämfört med endast den första. Tydliga skillnader i oxidation för filmerna samt förluster av jodligand kunde identifieras för de olika förvaringsmiljöerna, med bäst stabilitet uppvisad av filmerna som förvarades i argonatmosfär.

Lateral self-exchange of charge across dye-sensitized film is a phenomenon that may play animportant role in effectivizing H2 production from water via solar energy, and shows potential forother interesting applications. The rate of charge movement via lateral self-exchange across afilm is often quantified in terms of apparent diffusivity of charge, Dapp. In this project, it wasinvestigated how Dapp varies with applied potential, as preliminary results had shown resultsinconsistent with current theoretical understanding. To examine this discrepancy, Dapp wascalculated for different applied overpotentials on a ZrO2 film sensitized with the dye D35. It wasconcluded that values of Dapp vary with overpotential close to the dye’s redox potential, aspredicted by theory. Different dyes may yield other results, and further research on the subject isneeded. Interesting and unexplained differences in kinetics for oxidation and re-reduction of thedye were found, which prompts further studies on the matter.

Hos vissa grupper är sockerkonsumtionen för hög i dagens samhälle. Sackaros som är en annan benämning för strösocker, har hög energitäthet men innehåller inga mikronäringsämnen. Vid en hög konsumtion av sackaros ökar risken för att få i sig tillräcklig mängd av mikronäringsämnen. Dessutom kan det även medföra ett för högt energiintag som i sin tur ökar risken att drabbas för diabetes och hjärt-kärlsjukdomar. Det kan därför vara lämpligt att reducera mängden tillsatt sackaros i livsmedel. Ett populärt livsmedel där sackaros utgör en betydande del är glass. Syftet med detta examensarbete var att utveckla en jordgubbssorbet där halten fruktpuré var så stor som möjlig och mängden tillsatt sackaros var minimal. Då den totala halten socker är kritisk för den upplevda smaken och helhetsintrycket av en sorbet, var det undersökta intervallet av tillsatt sackaros begränsat. De jordgubbssorbeter som undersöktes hade en total sackaros-halt på 20,3%, 18,7% och 17,1%. De metoder som användes under arbetet för att undersöka sambandet mellan sackarosinnehållet och sorbetens egenskaper var fryspunktsbestämning, smälthastighetsanalys, mikroskopering, bestämning av inkorporerad luft och sensorisk utvärdering. De genomförda analyserna på de olika sorbetsammansättningarna visade att mängden tillsatt sackaros påverkade sorbetens fysikaliska och sensoriska egenskaper. Den sorbet med lägst halt tillsatt sackaros hade högst fryspunkt och smälthastighet men minst mängd inkorporerad luft utifrån mikroskopanalys och overrun-beräkningar. Detta till skillnad från den sorbet med högst halt tillsatt sackaros som hade motsatta värden med lägst värden på fryspunkt och smälthastighet och mest mängd inkorporerad luft. Den sensoriska utvärderingen av de olika tillverkade sorbeterna påvisade en signifikant skillnad i textur, så som mjukhet och isighet. Inga signifikanta skillnader kunde däremot påvisas för de andra sensoriska egenskaperna som testades (färg, förväntad upplevelse, sötma och fruktighet). Intressant nog var ingen av de tillverkade sorbetsammansättningarna som ansågs vara en sämre produkt än originalprodukten med en tillsatt sackaros-halt på 20,3%.   Sammanfattningsvis har detta examensarbete visat på möjligheten att minska mängden tillsatt sackaros i livsmedel så som sorbet och fortfarande erhålla en likvärdig produkt. En liten minskning av socker i flera livsmedel kan på sikt bidra med ett lägre intag av tomma kalorier, vilket kan vara bra för folkhälsan. / In some groups, sugar consumption is too high in today's society. Saccharose, another term for granulated sugar, has a high energy density but contains no micronutrients. With a high consumption of saccharose, the risk of ingesting a sufficient amount of micronutrients increases. In addition, it can also lead to an excessive energy intake, which in turn increases the risk of developing diabetes and cardiovascular disease. It may therefore be appropriate to reduce the amount of added saccharose. A popular food where saccharose makes up a significant portion is ice cream. The purpose of this thesis was to develop a strawberry sorbet where the content of fruit puree was as large as possible and the amount of added saccharose was minimal. As the total sugar content is critical for the perceived taste and overall impression of sorbet, the range of added saccharose examined was limited. The strawberry sorbets examined had a total saccharose content of 20.3%, 18.7% and 17.1%. The methods used during the work to investigate the relationship between the saccharose content, and the properties of the sorbet were freezing point determination, melting rate analysis, microscopy, determination of incorporated air and sensory evaluation. The analyzes performed on the different sorbet compositions showed that the amount of added saccharose affected the physical and sensory properties of the sorbet. The sorbet with the lowest added saccharose had the highest freezing point and melting rate but the least amount of incorporated air based on microscope analysis and overrun calculations. This contrasts with the sorbet with the highest content of added saccharose which had opposite values ​​with the lowest values ​​of freezing point and melting rate and the most amount of incorporated air. The sensory evaluation of the various manufactured sorbets showed a significant difference in texture, such as softness and iciness. However, no significant differences could be detected for the other sensory properties tested (colour, expected experience, sweetness and fruitiness). Interestingly, none of the manufactured sorbet compositions was a worse product than the original product with an added saccharose content of 20.3%. In summary, this thesis has shown the possibility of reducing the amount of added saccharose in foods such as sorbet and still obtaining an equivalent product. A small reduction in sugar in several foods can in the long run contribute to a lower intake of empty calories, which can be good for public health.