Improving the identification ability of surfaced-immobilized nucleic acid probes for small size DNA or RNA targets, utilizing optical or electrochemical methods, has been the goal for the gene chip technology. This study focuses on new probe design for introducing hairpin structural features and locked nucleic acid modification. We use three kinds of probes (DNA-LN, DNA-HP and LNA-HP) to prepare recognition layers via self-assembly processes on a gold substrate, and utilize AFM-based nanolithography technique to produce nanofeatures to observe the stiffness changes of oligonucleotide chains resulting from the formation of rigid double stranded duplexes when target sequence hybridizes to the probe. We also monitor the topographic changes upon exposure to the single mismatched and non-complementary targets as a function of time. The results reveal LNA-HP probes exhibit the highest response to discriminating single-point mutation in the base sequence. In addition, we study the effects of salt concentration, reaction temperature and the small size on the hybridization efficiency.

With the raise of nanotechnology researching, many special physical and chemical properties were found gradually in nanoscale. Among them, the one-dimension nanostructure owns high specific surface area and excellent electron emission properties. Moreover, the two-dimension arrayed nanostructure has the characteristics of photonic crystal and moth-eye effect. Currently, advanced lithographic methods such as electron beam (E-beam) or deep ultraviolet (DUV) lithography and X-ray lithography are adopted to define periodic nanoscale patterns. But these lithographic equipment are too expensive. Moreover, costly etching methods such as inductively coupled plasma reactive ion etching (ICP-RIE) or electron cyclotron resonance reactive ion etching (ECR-RIE) must be used to form arrayed silicon nanostructure with high aspect ratios. The nanoscale array patterns can be defined on the surface of the silicon wafer by the self-assembly of a polystyrene nanosphere. The photo-assisted electrochemical etching (PAECE) has the advantage of forming nanopore, and the aspect ratio of etched nanopores can be as high as 50:1 which is better than ICP-RIE. Therefore, PAECE is very suitable to fabricate nanostructure. This high-cost drawback makes most of academias and small/medium enterprises hard to invest in nanotechnology. This study combines the self-assembly nanosphere lithography (SANSL) process and photo-assisted electrochemical etching to fabricate a nanostructure array with a high aspect ratio on the surface of a silicon wafer. Experimental results show that the nanosphere array with a nearly perfect arrangement can be obtained in the sample of 1.8 ∗1.8 cm2 by spin coating and vibration coating. Using reactive ion etching (RIE) can transfer the nanosphere array pattern to the silicon nitride layer, and form the etching window of PAECE. The concentration of the HF electrolyte used in PAECE was 2.5 wt%. When PAECE was performed with etching mask can produce deeper and periodic nanopores. The surfactant of SDSS added in the HF electrolyte of PAECE can reduce the contact angle of electrolyte and avoid the phenomenon of hole-reaming. When the voltage of 1 V is used to etch for 12.5 min, the etching depth of the nanopore array structure is about 5.69 £gm and its diameter is about 90 nm, such that the aspect ratio of the pore can reach about 63:1. If the etching voltage was increased, the width of pore will be increased and the depth of pore will be reduced gradually at the same time. When the etching voltage of 2 V is applied to etch for 5 min, the etching height of the nanopillar is about 2 £gm and its diameter is about 100 nm, such that the aspect ratio of the pillar can reach about 20:1. The nanopillar was arranged periodically according to the definition of nanosphere, therefore the arrayed nanopillar can be realized successfully. Dropping the solution which has biological samples into the gap of nanopillar, it will affect the light which goes through the nanostructure and produce specific parameters of polarization. The results showed that when the DI water was dropped into the nanopillar structure, the degree of polarization (DOP) is 0.981, azimuth is 4.86¢X and ellipticity is 2.83¢X. When the solution which has alkaline lysis plasmid of 5 £gg/ml was dropped into the nanopillar structure, the DOP is 0.957, azimuth is 7.7¢X and ellipticity is 3.99¢X. The result shows that the change of polarization parameter has the relations with the concentration of biological samples in solution. Therefore, the measure system can be combined with nanopillar array to develop the photonic crystal biosensor. This study also applies the developed nanopore nanostructure array to fabricate sub-wavelength antireflection structure of solar cell. Experimental results show that the deeper in structure and then the better in antireflective effect. After performing 1 V PAECE for 5 min, the weighted mean reflectance can be reduced to 1.73% under the wavelength range of 280¡V890 nm. Further coating of a silicon nitride layer on the surface of a nanostructure array reduces the weighted mean reflectance even to 0.878 %. Finally, this study also uses various voltage of PAECE to produce nanostructure array with different surface area for the electrode fabrication of fuel cell. Experimental results show that the larger in surface area of sample and then the better in catalysis effect. Two-staged PAECE of 1.5 V and 1.75 V can yield nanopillar with surface area of 14.2 cm2 , which is about 50.2 times higher than a planar electrode. When the surface of such a nanopillar array is coated with platinum of 1000 Å, the reaction current of nanopillar array is 10.2 mA, which is 72.9 times higher than that obtained by only a planar electrode.

In order to gain insights into the electronic interactions between metallic gold and self-assembled monolayers composed of π-conjugated thiols, a series of thiol-containing molecules based on a stilbene backbone were synthesized and assembled on gold surface. The resulted monolayers were characterized with a variety of surface-sensitive techniques and the electronic properties of the obtained surfaces were studied with the use of ultraviolet photoelectron spectroscopy. Work-function changes and alignment of the molecular energy levels with respect to the Fermi level of the metal were investigated and important insights regarding the electronic properties of the metal / organic interfaces were obtained. Another aspect of interactions between organic dyes and metallic gold was studied in the context of spectroscopic properties of systems incorporating gold nanoparticles with organic fluorophores covalently attached to the nanoparticle surface. Ultrafast dynamics of the excited-state deactivation of the organic fluorophores attached to the surface of gold nanoparticles were studied with the use of a fs transient absorption technique. It was found that the close proximity of a gold nanoparticle had a profound impact on the excited-state lifetime of the studied organic fluorophore. The influence of the structure of the studied systems on the excited-state deactivation dynamics of the organic fluorophores was described.

Silicon carbide (SiC) has been around for more than 100 years as an industrial material and has found wide and varied applications because of its unique electrical and thermal properties. In recent years there has been increased attention on SiC as a viable material for biomedical applications. Among these applications are those where SiC is used as a substrate material for biosensors and biotransducers, taking advantage of its surface chemical, tribological and electrical properties. In this work we have used the proven bio- and hema-compatibility of SiC to develop a viable biorecognition interface using SiC as the substrate material for myocardial infarction detection. The approach followed included the development of an electrochemical-based sensor in which 3C-SiC is used as the active electrode and where flat band potential energy changes are monitored after successive modification of the SiC with aminopropyltriethoxysilane, anti-myoglobin and myoglobin incubation. We have studied the quality of self assembled monolayers obtained by surface modification of SiC using organosilanes such as aminopropyltriethoxysilane and octadecene, which is the starting point for the immobilization of cells or proteins on a substrate. We employed this technique on 6H-SiC where we were able to control the proliferation of H4 human neuroglioma and PC12 rat pheochromocytoma cells in vitro. Finally, aminopropyltriethoxysilane (APTES) was successfully used to immobilize anti-myoglobin on the 3C-SiC electrodes as demonstrated by fluorescence microscopy results. The electrical characterization of the surfaces was performed via impedance spectroscopy and by measuring changes in flat band potential using the Mott-Schottky plot technique. Changes in flat band and impedance of the SiC/antibody/protein interface would allow us to detect changes in the space charge region of the semiconductor. However, we believe that because of the presence of surface states and different crystal defects on the 3C-SiC we did not observed repeatable results that allowed us to identify the presence of myoglobin in solution. In addition, certain modifications need to be performed to the electrochemical cell in order to confirm the presence of the myoglobin immobilized on the functionalized SiC surfaces.

Studies of biomolecular interactions are of interest for several reasons. Beside basic research, the knowledge gained from such studies is also very valuable in for example drug target identification. Medical care is another area where biomolecules may be used as biomarkers to aid physicians in making correct diagnosis. In addition, the highly specific interactions between antibodies and almost any substance opens up the possibilities to design systems for detection of trace amounts of both biological and non-biological substances within environmental restoration, law enforcement, correctional care, customs service and national security. A biochip, which contains a biologically active material, offers a means of monitoring the molecular interactions in the above applications in a sensitive and specific manner. The biochip is a key component of a biosensor, which also includes components for transforming the interaction events into a human-readable signal. This thesis describes the use of poly(ethylene glycol) (PEG) in biochip design. Two different approaches are presented, the first based on ethylene glycol (EG)-containing alkyl thiol self-assembled monolayers (SAMs) on flat gold and the second on photo-induced graft copolymerisation of PEG-containing methacrylate monomers onto various substrates. The former is a two dimensional system where EG-terminated thiols are mixed with similar thiols presenting tail groups that mimic the explosive substance 2,4,6-trinitrotoluene (TNT). In an immunoassay, the detection limit for TNT was determined to fall in the range 1-10 µg/L. In the second approach, a branched three dimensional biosensor matrix (hydrogel) is proposed. The carboxymethylated (CM) dextran matrix, which is commonly used within the biosensing community, is not always ideal for studies of biointeractions, due to the non-specific binding frequently encountered in work with complex biological solutions and various proteins. To employ PEG, which displays a low non-specific binding of such species, is therefore an interesting option worth investigating. The use of a branched graft polymerised PEG matrix in biosensor applications is novel as compared to previous reports which have focused on linear PEG chains. The latter approach provides, at maximum, one functional group, per surface anchoring point, for immobilisation of sensor elements. Thus, it has the inherited disadvantage that it limits the number of available immobilisation sites. The present PEG matrix contains a large number of functional groups, for immobilisation of sensor elements, per grafting site and offers the potential of improved response upon binding to the analyte as demonstrated in a series of successful sensor experiments. Furthermore, the nature of the process enables easy preparation of matrix patterns and gradients. In a PEG matrix gradient, protein permeability is studied and the capabilities of immobilising proteins are demonstrated. By combining the patterning technique with different monomers in a two-step process, an inert platform, lacking chemical attachment sites, is provided with arrays of spots (with immobilisation capabilities), which are conveniently addressed via microdispensing and used for biosensor purposes. The EG-terminated thiols present another means of generating such inert platforms, a route which is also investigated. To further explore the sensor quality of these spots, the concepts of patterning and gradient formation are combined and studied. / Det är intressant att studera biomolekylära interaktioner av många anledningar. För att kunna bedriva framgångsrik läkemedelsutveckling är det oerhört viktigt att känna till hur olika molekyler samverkar i människokroppen. Inom sjukvården kan biomolekyler användas som biomarkörer, då närvaro av dem eller förändringar av deras koncentrationer är kopplade till sjukdomstillstånd, och därmed hjälper läkaren att ställa rätt diagnos. Dessutom kan de mycket specifika interaktionerna mellan antikroppar och (i princip) valfri substans användas för detektion av spårämnen vid miljösaneringsarbete, gränskontroller, polisarbete, fängelser och arbete med nationell säkerhet. Den här avhandlingen beskriver hur polymeren polyetylenglykol (PEG) kan användas vid design av biochip. Ett biochip är en liten anordning, som kan användas för att detektera specifika molekyler med hjälp av en biologisk interaktion. Traditionellt har PEG använts inom biomaterialsektorn, men återfinns även i hygienartiklar som tvål och tandkräm. Ett annat användningsområde är konservering av bärgade träskepp och i en del litiumjonbatterier ingår PEG som en komponent. Dessutom pågår utveckling av PEG-innehållande skyddsvästar. I det här arbetet används PEG framför allt på grund av sin förmåga att minimera ospecifik inbindning av proteiner, som utgör en stor del av gruppen biomolekyler, till ytor på biochip. Två olika typer av ytbeläggningar, som innehåller den här polymeren, har använts. Den första typen ger mycket tunna (~0.000003 mm), tvådimensionella filmer medan den andra ger en något tjockare (~0.00005 mm), tredimensionell struktur (matris). De tvådimensionella filmerna har använts för att utveckla en sprängämnesdetektor med mycket hög känslighet (detektionsgräns mellan 1-10 ppb). En viktig beståndsdel i detta system är antikroppar riktade mot sprängämnet trinitrotoluen (TNT). Den tredimensionella matrisen är mer generell och kan användas för att studera många olika molekylära interaktioner. Tillverkningsmetoden av matrisen är baserad på belysning med ultraviolett ljus och är därmed lämpad för att skapa mönstrade ytor. Genom att blockera delar av ljusflödet begränsas tillväxten av matrisen till de belysta delarna. På så sätt har bland annat så kallade mikro-arrayer, bestående av mikrometerstora (tusendels millimeter) strukturer i ett regelbundet mönster, tillverkats. Tekniken tillåter även tillverkning av gradienter, där matrisens tjocklek varierar längs med provet, genom att belysa olika delar av provytan olika länge. Genom att undersöka dessa gradienter har information om matrisens genomsläpplighet för proteiner kunnat extraheras. Gradientkonceptet har även kombinerats med mikro-arraytillverkningen och gett möjlighet att studera interaktioner mellan flera olika modellproteiner och deras motsvarande antikroppar i olika tjocka matriser på en och samma yta. Det finns ett stort antal sätt att utnyttja interaktionerna mellan olika molekyler på ett biochip. Ett tilltalande tillvägagångssätt är exempelvis att i en mikro-array binda in olika molekyler som kan fånga kliniskt intressanta biomolekyler, i syfte att skapa en hälsoprofil. Ett sådant biochip skulle ge möjlighet att parallellt detektera eller bestämma koncentrationen av ett stort antal biomolekyler i till exempel en droppe blod. På så sätt kan en diagnos snabbt ställas, kanske till och med utan att patienten behöver uppsöka sjukvården. Den utvecklade PEG-matrisen har god potential att fungera i en sådan applikation.

Reactive ion scattering spectrometry (RISS) utilizing low energy (tens of eV) polyatomic ions was employed to characterize self-assembled monolayers (SAMs) on gold. The terminal composition of halogenated SAMs, chemisorption motifs of disulfide and diselenide SAMs, and electron transfer properties of molecular wire containing SAMs were interrogated to develop the versatility of RISS as an analytical surface characterization technique.Novel halogen terminated SAMs were examined for their ability to convert translational to vibrational energy of colliding projectile ions. A general increasing energy deposition trend correlated with increasing terminal mass with the exception of the iodine functionality. Increased amounts of surface abstractions and sputtering from C12I suggest competitive ion-surface interactions account for less than predicted energy deposition results. Mixed films of CH2Br and CH3 terminal groups elucidated interfacial surface crowding discerned by energy deposition results.Thiol and disulfide based SAMs were shown by RISS comparisons to be dissimilar in structure. Terminal orientation, however, was the same based on ion-surface reactions, disproving the proposed dimer model of disulfide SAMs. Ion-surface reactions and electron transfer properties of disulfide surfaces suggested greater percentages of c(4x2) superlattice structure than in thiol SAMs. Based on increased hydrogen reactivity, decreased methyl reactivity, and increased energy deposition results, diselenide based SAMs were more disordered than S-Au based SAMs. Electron transfer results monitored through total ion currents (TIC) showed Se-Au contacts are more conductive than S-Au attachments.Molecular wire candidates whose electron transfer capabilities are difficult to characterize by traditional techniques were characterized by RISS after being doped into matrix SAMs. Electron transfer properties were dependent on the isolating SAM matrix, dipole moments of the wires, and the potential applied to the surface. Changes in surface voltage dictated molecular wire geometry and electron transfer. Wires were annealed into preferential geometries by colliding ions, but did not operate as switches.While not related to the advancement of RISS, structural elucidation of the pharmaceutical carvidioliol was investigated by collision-induced dissociation, surface-induced dissociation, sustained off-resonance irradiation, and sustained off-resonance irradiation-resonant excitation and through gas-phase hydrogen/deuterium exchange. This molecule fragmented easily by all methods and demonstrated the chemical specificity of gas-phase hydrogen/deuterium exchange experiments.

Nowadays, material, energy and information technologies are three pillar industries. The materials that have close relation with our life have also been the foundation for the development of energy and information technologies. As the new member of the material family, functional molecular materials have become increasingly important for many applications, for which the design and characterization by the theoretical modeling have played the vital role. In this thesis, three different categories of functional molecular materials, the endohedral fullerenes, the fullerene derivatives and the self-assembled monolayers (SAMs), have been studied by means of first principles methods. The non-metal endohedral fullerene N@C60 is a special endohedral fullerene that is believed to be relevant to the construction of future quantum computer. The energy landscape inside the N@C60 has been carefully explored by density functional theory (DFT) calculations. The most energy favorable potential energysurfaces (PESs) for the N atom to move within the cavity have been identified. The effect of the charging on the PESs has also been examined. It is found that the inclusion of dispersion force is essential in determining the equilibriumstructure of N@C60. Furthermore, the performance of several commonly useddensity functionals with or without dispersion correction has been verified for ten different endohedral fullerenes A@C60 with the atom A being either reactive nonmetal or nobel gases elements. It shows that the inclusion of the dispersion forcedoes provide better description for the binding energy (BE), however, none ofthem could correctly describe the energy landscape inside all the ten endohedral fullerenes exclusively. It thus calls for the further improvement of current density functionals for weak interacting systems. Soft X-ray spectroscopy is a powerful tool for studying the chemical and electronic structures of functional molecular materials. Theoretical calculations have been proven to be extremely useful for providing correct assignments for spectraof large systems. In this thesis, we have performed first principles simulations forthe near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectra (XPS) of fullerene derivatives and aminothiolates SAMs. Our calculatedspectra can accurately reproduce experimental results available for all the systemsunder investigations, and identify the species or structures that are responsible for those unexpected spectral features observed in experiments. We have suggested a modified building block (MBB) approach that allows to calculate NEXAFS spectraof a large number of fullerene derivatives with very small computational cost, and resolved the long standing puzzle around the experimental XPS and NEXAFS spectra of SAMs with aminothiolates. / <p>QC 20120523</p>

Atmospheric corrosion indoors is of great practical importance for the degradation of metals, for example in electronics, military equipment, and cultural heritage items. It involves a wide range of chemical, electrochemical, and physical processes occurring in gas, liquid, and solid phases, and at the interfaces between them. Hence, a molecular understanding of the fundamental interactions during atmospheric corrosion is of utmost importance. Copper is one of the most used metals in electrical contacts, power generators, heat exchangers, etc. and is prone to indoor atmospheric corrosion. Although corrosion and oxidation of copper in the presence of corrosion stimulators is thermodynamically inevitable, there are ways to reduce the kinetics of corrosion and oxidation reactions. Self assembled monolayers (SAMs) of organic molecules, when adsorbed on copper surfaces, have proven to be efficient barriers against copper corrosion. However, understanding at the molecular level of the initial stages of corrosion of SAM covered copper in atmospheric corrosion conditions is lacking. The main reason is the inability of the conventional analytical methods to detect and characterize very thin corrosion products formed during the initial stages (from seconds to days) of atmospheric corrosion of SAM covered copper. To overcome this situation a highly surface sensitive technique, vibrational sum frequency spectroscopy (VSFS), has been utilized in situ and ex situ in this thesis to detect and follow the oxidation of alkanethiol SAM covered copper in dry air as well as to assess the conformational changes of SAM molecules during oxidation.  A very sensitive gravimetric method, quartz crystal microbalance with dissipation monitoring (QCM-D), and a highly sensitive and versatile optical technique, nanoplasmonic sensing (NPS), were combined in situ with VSFS to quantify this very slow oxidation process. This combination allowed the heterogeneity of the oxidation process as well as the mass and the rigidity of the corrosion products to be detected simultaneously. To address indoor atmospheric corrosion conditions where carboxylic acids play an important role we next studied the interaction between SAM covered copper and humidified air, to which formic acid was added. The in situ identification of the corrosion products and their formation kinetics was done using near surface sensitive infrared reflection/absorption spectroscopy (IRAS), and the effect of hydrocarbon chain length in alkanethiol SAMs on their corrosion protection efficiency was investigated. The effect of the anchoring group in the SAMs on their corrosion protection efficiency was studied for hexaneselenol using -SeH as the anchoring group, and the results were compared with its thiol counterpart, hexanethiol, with -SH as the anchoring group. Complementary in situ and ex situ VSFS measurements were performed to assess the quality of the SAMs before, during, and after exposure. It was shown that the SAMs of alkanethiols greatly inhibited the formation of copper (I) oxide and slowed down the formation of other corrosion products, i.e. copper formate and copper hydroxid. This was due to a selective hindrance of the corrosion stimulators, oxygen, water, and formic acid molecules reaching the copper-SAM interface. The corrosion inhibiting effect increased with the hydrocarbon chain length. The SAMs of hexaneselenols, on the other hand, exhibited an accelerated formation of copper (I) oxide, copper formate and copper hydroxide compared to an unprotected surface as a result of the partial removal of hexaneselenol molecules from the copper surface during prolonged exposure. The experience gained in characterizing and quantifying thin copper oxides was further used to explore the influence of gamma (γ) radiation on copper corrosion in anoxic water. This multi-analytical approach included IRAS, cathodic reduction, confocal Raman microscope, atomic force microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and inductively coupled plasma - atomic emission spectroscopy. The results clearly showed that copper dissolution as well as the oxide layer thickness increase with gamma radiation under the exposure conditions. / Atmosfärisk korrosion under inomhusförhållanden är av stor praktisk betydelse på grund av dess inverkan på exempelvis vårt kulturarv i museimiljöer, tillförlitligheten hos elektronik i olika industriella sammanhang, eller militär utrustning förvarad i olika förråd. Den atmosfäriska korrosionen styrs av ett brett spektrum av kemiska, elektrokemiska och fysikaliska processer som äger rum i tre faser: atmosfären, den tunna fuktfilmen på objektytan och den fasta fasen, samt i de bägge fasgränserna mellan de tre faserna. För att kunna hitta motmedel mot korrosionen är det av yttersta vikt att öka den molekylära förståelsen för dessa processer. Koppar är en mycket använd metall i elektriska eller elektroniska komponenter, i värmeväxlare eller VVS-sammanhang, som beslag och i en rad olika dekorer. Metallen korroderar eller oxiderar spontant i många korrosiva miljöer, men det finns ett brett spektrum av metoder för att minska korrosions- eller oxidationshastigheten. Monoskikt av tätpackade självassocierande organiska molekyler (engelska: self assembled monolayers, förkortat SAM) adsorberade på kopparytan har visat sig vara effektiva barriärer för kopparkorrosion. Den molekylära insikten i dessa monoskikts funktionssätt för att minska den atmosfäriska korrosionen är dock ännu rätt så begränsad. Den främsta orsaken är oförmågan hos mer etablerade analytiska metoder att kunna karakterisera de ytterst små mängder av korrosionsprodukter som bildas under den atmosfäriska korrosionens inledande skeenden upp till några dagars exponering. Den extremt ytkänsliga och i korrosionssammanhang fortfarande relativt oprövade analysmetoden summafrekvensspektroskopi (engelska: vibrational sum frequency spectroscopy, förkortat VSFS) har därför använts för att under pågående exponering följa det mycket långsamma oxidationsförlopp som uppstår när koppar, skyddat av något organiskt monoskikt, exponeras för torr luft. VSFS har även kunnat användas för att under pågående oxidation följa strukturella förändringar hos monoskiktet. För att kvantifiera en så långsam oxidationsprocess har även en annan extremt masskänslig metod kunnat kombineras med VSFS, en kvartskristallmikrovåg med s.k. dissipationsövervakning, förkortat QCM-D. Ytterligare en i korrosionssammanhang oprövad men lika masskänslig teknik har kunnat kombineras med VSFS. Den metoden besitter än så länge bara ett engelskt namn, nanoplasmonic sensing (NPS). Kombinationen VSFS–QCM-D–NPS har utnyttjats i en serie unika försök, där inte bara de ytterst långsamma oxidationshastigheterna kunnat mätas upp, utan även andra viktiga faktorer såsom graden av heterogenitet i den bakomliggande oxidationsprocessen. För att närma sig en miljö som kan efterlikna korrosiva inomhusförhållanden har atmosfären i nästa steg befuktats och dessutom har låga halter av myrsyra tillsats. Just tillsatsen av karboxylsyror har visat sig generera korrosionsprodukter med en sammansättning som på koppar och vissa andra metaller efterliknar de som bildas under atmosfärisk korrosion inomhus. Identifiering av korrosionsprodukter och deras tillväxthastighet på koppar, skyddat av olika långa tätpackade kolkedjor med en tiolgrupp i ena ändan som binder till kopparsubstratet, har kunnat ske med infraröd reflektions-absorptionsspektroskopi (IRAS) under in situ-förhållanden. Ju längre kolvätekedjor desto större korrosionsinhibieringsförmåga kunde påvisas. När den på koppar förankrade tiolgruppen ersattes med en selenolgrupp blev korrosionsinhibieringsförmågan sämre. Kompletterande mätningar in situ och ex situ  utfördes med hjälp av VSFS för att undersöka kvaliteten på de tätpackade kolvätekedjorna, varvid kunde påvisas att graden av tätpackning hos kolkedjorna försämrades med ökad exponeringstid. Förutom den allmänna nedbromsningen av korrosionshastigheten på koppar blev sammansättningen av bildade korrosionsprodukter på oskyddat koppar en annan än på  koppar skyddat av tioler. I det förra fallet detekterades korrosionsprodukterna koppar(I)oxid, koppar(II)format och koppar(II)hydroxid, under det att ingen koppar(I)oxid påvisades på skyddat koppar, endast små mängder koppar(II)format och koppar(II)hydroxid kunde detekteras. De adsorberade kolkedjorna tycks hindra de korrosionsstimulerande molekylerna vatten, myrsyra och syrgas från att nå kopparytan lika effektivt. När de tiolförankrade kolvätekedjorna ersattes med selenolförankrade kolvätekedjor desorberades en del kolvätekedjor från kopparsubstratet vid längre exponeringstider. Resultatet blev att mängden korrosionsprodukter nu blev signifikant större än på oskyddat koppar, sannolikt på grund av galvanisk korrosion. Erfarenheterna från detta doktorsarbete vad gäller kvantifiering av små mängder kopparoxider har även utnyttjats för att undersöka inverkan av g-strålning på kopparkorrosion i rent vatten. Härvid användes ett multianalytiskt angreppssätt bestående av IRAS, katodisk reduktion, konfokal Ramanmikroskopi, atomkraftsmikroskopi, svepelektronmikroskopi, fotoelektronspektroskopi, samt analys av utlöst mängd koppar i vattenlösningen med induktivt kopplad plasmaatomemissionsspektroskopi. Resultaten visar tydligt att utlösningen av koppar, liksom det bildade oxidskiktets tjocklek, ökar med g-strålningen under rådande exponeringsförhållanden. / <p>QC 20131206</p>

Implanted combination devices comprising both biological as well as biomaterial components may trigger non-specific inflammatory responses against the biomaterial component as well as specific immune responses against the biological component. This specific immune response may be enhanced by the biomaterial, thereby implying a biomaterial-mediated adjuvant effect, or in contrast may be mitigated by the biomaterial. Since adjuvants function by triggering dendritic cell (DC) maturation, biomaterials may regulate DC responses and hence facilitate DC-orchestrated host responses. This research work has focused on examining DC responses to different model self-assembled monolayer (SAM) biomaterial chemistries, as an in vitro readout of the potential of these biomaterials to trigger DC maturation. The underlying hypothesis was that DCs recognize and respond to biomaterials either indirectly through the adsorbed protein layer, specifically through carbohydrate modifications of these proteins, or through carbohydrates inherent in the biomaterial chemistry, using PRRs to initiate an immune response. Towards this goal, DCs were derived from human peripheral blood mononuclear cells (PBMCs) by culture with DC differentiation cytokines and the culture systems were characterized as being composed of DCs as well as associated T and B lymphocytes. Culture of DCs on different SAM chemistries implied differential DC responses in terms of morphology, maturation marker expression and allostimulatory capacities as well as distinct underlying mechanisms responsible for these responses. Enzyme-linked lectin (ELLA) assays were used to characterize the profiles of carbohydrates associated with serum/plasma proteins adsorbed to different SAM chemistries. Differential profiles of DC carbohydrate ligands of CLRs were present on different chemistries. Furthermore, the profiles of human serum/plasma proteins adsorbed to and eluted from different SAM chemistries were assessed using immunoblot analysis. Finally, to observe the roles of carbohydrates in supporting DC maturation in the presence of a biomaterial, DCs were cultured in the presence of partially de-glycosylated FBS from which DC carbohydrate ligands were selectively removed. This research is significant towards the ultimate development of optimal design criteria for biomaterials for use in diverse tissue-engineering or vaccine development applications for which a wide spectrum of adjuvant effects are required.

This thesis examines the electro-optic, electric and electrochemical properties of liquid crystal (LC) materials in self-assembly systems, that is, liquid crystal-polymer electrolyte composites (LC-PEs), LC binary mixtures, and their potential application in dye-sensitised solar cells (DSSCs). The birefringence of LCs causes light modulation, which can be controlled by an applied voltage and electric field. In particular, the LCs are used as one of the components for the electrolyte redox couple which is responsible for charge transfer mechanism in DSSCs. In this work, LC-PEs were developed by dissolving LCs in polymer electrolytes; using a homologous series of cyanobiphenyls in a range of concentrations, alkyl chain lengths and dielectric permittivities. We found that doping the polymer electrolyte with 15% 4'-cyano-4'-pentylbiphenyl (5CB) improved ionic conductivity by up to 13 % compared to pure polymer electrolyte. Materials with positive dielectric permittivity and shorter alkyl chain length have been identified to be compatible with iodide/triiodide (I^-/I_3^-)-based polymer electrolytes. In DSSCs, 15% 5CB and 15% E7 LC-PEs exhibited the best efficiencies of 3.6 % and 4.0 %, respectively. In addition to LC-PEs, the self-assembly properties of smectic phase LCs were also utilised as templates for controlling the polymer structure in polymer electrolytes. A porous polymer network was prepared using various techniques including self-assembly, by applying an electric field and using a polyimide (PI) alignment layer. We found that the electrochemical and photovoltaic properties of these materials strongly correlated to the morphology/structure with the self-assembled structure, thus showing the best photovoltaic performance (5.9 %) even when compared with a reference solar cell (4.97 %). Finally, this thesis explores the interaction of LCs with graphene (Gr) in DSSC device architectures. Gr-based DSSCs were fabricated using different processing conditions, with the result being that Gr improved the performance of the DSSCs. The highest efficiency obtained was 5.48 % compared to the 4.86 % of a reference DSSC. The incorporation of LC-PEs in Gr-based DSSCs improved the performance of DSSCs was observed in devices with low concentrations of LCs due to the Gr inducing planar alignment of LCs. These results suggest a new strategy to improve DSSC efficiency by incorporating LC materials in the polymer electrolyte component. Even though these LCs are highly insulating, their self-assembly and dielectric polarisability help enhance ionic conductivity and optical scattering when doped into polymer electrolytes. This work can be extended in a fundamental way to elucidate the ionic conduction mechanism of LC-based electrolyte systems. Furthermore, it would be interesting if the benefits of using LC-PEs and smectic-templated polymer electrolytes (Sm-Pes) can be translated further in commercial electrochemical energy conversion systems.