Optische Polymerfasern stellen ein relativ neues Medium zur Hochgeschwindigkeitsdatenübertragung mittels moduliertem Licht dar. Sie gestatten die Verbreitung großer Datenmengen über Entfernungen bis zu ca. 100 m, ohne eine Beeinflussung durch externe elektromagnetischen Feldern. Jedoch reagieren die Fasern und somit auch ihre optischen Eigenschaften aufgrund des organischchemischen Faseraufbaus empfindlich auf das Klima ihrer Umgebung. Die Ursachen für die Abnahme der optischen Transmission aufgrund von klimatischen Einflüssen (Alterung, Degradation) werden mittels chemisch analytischer Verfahren wie Chemilumineszenz (CL) und Fourier Transform Infrarot (FTIR) Spektroskopie untersucht. Dabei kommen fünf, von verschiedenen Herstellern bezogene, Multimode- POFs aus PMMA in sieben verschiedenen Klimaten zum Einsatz. Drei dieser fünf POFs werden genauer untersucht, um den Einfluss einzelner Parameter festzustellen und optische Langzeitstabilität aufgrund von Kurzzeittests vorherzusagen. Als erstes erfolgt eine Kennzeichnung unbeanspruchter POF Komponenten (Kern, Mantel und nackte POF als Kombination von Kern und Mantel) über ihre physikalischen und chemischen Eigenschaften. Die Glas- und die Schmelztemperaturen liegen im Bereich von 120 °C bis 140 °C, das Molekulargewicht des Kerns bei größenordnungsmäßig 105 g mol-1 ;. FTIR-Messungen zeigen zwar Unterschiede in der chemischen Zusammensetzung der Mäntel aber keine Unterschiede bei den Kernen. Bei zwei der POF Proben / die als Kabel (Kern, Mantel und Schutzhülle) für 3300 Stunden einem Klima aus 92 °C und 95 % relativer Feuchte (r.F.) ausgesetzt waren, verringern sich daraufhin die optische Transmissionen in unterschiedlicher Weise. Die Untersuchung der zugehörigen nackten POFs mittels CL, FTIR, Thermogravimetrie (TG), UV/VIS und Gel Permeation Chromatographie (GPC) lässt eine stärkere Schädigung der Mäntel als der Kerne vermuten. Wahrscheinlich führt eine starke Manteldegradation zu einer erhöhten Absorption und Fehlstellen im Mantel und damit zu einer Transmissionsabnahme. Daher scheint die optische Stabilität der POF stärker durch die thermo-oxidative Stabilität des Mantels bestimmt zu sein als durch die des Kernes. Drei nackte POFs (Kern und Mantel) sind unterschiedlich lang (30 Stunden bis 3000 Stunden) folgenden Klimaten ausgesetzt: 92 °C / 95 % r.F., 92 °C / 50 % r.F., 50 °C / 95 % r.F., 90 °C / geringe Feuchte, 100 °C / geringe Feuchte, 110 °C / geringe Feuchte and 120 °C / geringe Feuchte. Auch in diesen Klimaten ergaben sich probenbedingte unterschiedliche Transmissionsänderungen. Die Ergebnisse deuten stark darauf hin, dass bei gleichzeitig hoher Temperatur und hoher Feuchte physikalische Änderungen wie die Volumenausdehnung die Hauptursachen für die Abnahme der optischen Transmission bilden. Ein weiterer Einflussfaktor ist die chemische Zusammensetzung der Mäntel. Bei Kombination von hoher Temperatur und geringer Feuchte erzeugen in den Anfangsstadien der Alterung physikalische Änderungen Transmissionsabnahmen, vermutlich entstehen Fehlstellen in der Kern-Mantel-Grenzschicht. Hinzukommen in den späteren Stadien wahrscheinlich zunehmende Lichtabsorption in Kern und Mantel. L. Jankowski (Doktorand in der BAM) bestätigt diese Annahme durch parallel ausgeführte optische Simulationsrechnungen. Auch für nackte POFs scheint also die thermo-oxidative Stabilität die optische Stabilität zu bestimmen. Kurzzeitalterungstests sollen Aufschluss über den Einfluss individueller Klimaparameter auf die POF Eigenschaften geben. Es zeigt sich bei dauerhaft hoher Temperatur und variabler Feuchte aufgrund des physikalisch absorbierten Wassers bis zu einem gewissen Grad ein reversibles Verhalten des Transmissionsverlustes. Dieses Verhalten tritt aber nur kaum merkbar auf, wenn bei konstanter hoher Feuchte die Temperatur variiert wird. Bei Raumtemperatur und variabler Feuchte stellt sich jedoch ein voll reversibles Verhalten des Transmissionsverlustes ein. Die hier beschriebenen Untersuchungen sind als Ausgangspunkt für weitergehende Forschungen zu verstehen. Die begrenzte Zurverfügungstellung von POF Basisdaten durch die Hersteller und der zeitaufwendige klimabedingte Alterungsprozess beschränken die Ergebnisse mehr oder weniger auf die untersuchten Proben. Signifikante allgemeine Aussagen erfordern aber beispielsweise zusätzliche statistische Daten der Produktionsschwankungen von POF Eigenschaften. Dennoch besitzen die hier beschriebenen Tests das Potential für eine Annäherung an die optische Langzeitstabilität und deren Vorhersage. / Polymer optical fibers (POFs) are a rather new tool for high-speed data transfer by modulated light. They allow the transport of high amounts of data over distances up to about 100 m without be influenced by external electromagnetic fields. Due to organic chemical nature of POFs, they are sensitive to the climate of their environment and therefore the optical fiber properties are as well. Hence, the optical stability is a key issue for long-term applications of POFs. The causes for a loss of optical transmission due to climatic exposures (aging/degradation) are researched by means of chemical analytical tools such as chemiluminescence (CL) and Fourier transform infrared (FTIR) spectroscopy for five different (with respect to manufacturers) step-index multimode PMMA based POFs and for seven different climatic conditions. Three of the five POF samples are studied more in detail to realize the effects of individual parameters and for forecasting longterm optical stability by short-term exposure tests. At first, the unexposed POF components (core, cladding, and bare POF as combination of core and cladding) are characterized with respect to important physical and chemical properties. The glass transition temperature Tg, and the melting temperature Tm are in the region of 120 °C to 140 °C, the molecular weight (Mw) of cores is in the order of 105 g mol-1. POFs are found to have different chemical compositions of their claddings as could be detected by FTIR, but identical compositions of their cores. Two of the POFs are exposed as cables (core, cladding and jacket) for about 3300 hours to the climate 92 °C / 95 % relative humidity (RH) resulting in a different transmission decrease. Investigating the related unexposed and exposed bare POFs for degradation using CL, FTIR, thermogravimetry (TG), UV/visible transmittance and gel permeation chromatography (GPC) suggest that claddings of POFs are more affected than cores. Probably the observed loss of transmission is mainly due to increased light absorption and imperfections at the core-cladding boundary caused by a large degradation of claddings. Hence, it is highly possible that the optical transmission stability of POFs is governed mainly by the thermo-oxidative stability of the cladding and minor of the core. Three bare POFs (core and cladding only) are exposed for different duration of exposure time (30 hours to 4500 hours) to 92 °C / 95 %RH, 92 °C / 50 %RH, 50 °C / 95 %RH, 90 °C / low humidity, 100 °C / low humidity, 110 °C / low humidity and 120 °C / low humidity. In these climates their transmission variations are found to be different from each other, too. The outcomes strongly inform that under high temperature and high humid climates physical changes such as volume expansion, are the main sources for the loss of optical transmission. Also, the optical transmission stability of POFs is found to be dependent on chemical compositions of claddings. Under high temperature and low humid conditions, a loss of transmission at the early stages of the exposure is mainly caused by physical changes, presumable by corecladding interface imperfections. For the later stages of exposures it is proposed to an additional increase of light absorption by core and cladding owes to degradation. Optical simulation results obtained parallel by Mr. L. Jankowski (a PhD student of BAM) are found to confirm these results. For bare POFs, too, the optical stability of POFs seems to depend on their thermo-oxidative stability. Some short-term exposure tests are conducted to realize influences of individual climatic parameters on the transmission property of POFs. It is found that at stationary high temperature and variable humidity conditions POFs display to a certain amount a reversible transmission loss due to physically absorbed water. But in the case of varying temperature and constant high humidity such reversibility is hardly noticeable. However, at room temperature and varying humidity, POFs display fully reversible transmission loss. The whole research described above has to be regarded as a starting point for further investigations. The restricted distribution of fundamental POF data by the manufacturers and the time consuming aging by climatic exposures restrict the results more or less to the samples, investigated here. Significant general statements require for example additional information concerning the variation of POF properties due to production. Nevertheless the tests, described here, have the capability for approximating and forecasting the long-term optical transmission stability of POFs.<br> --------------<br> <i>Auch im Druck erschienen:</i><br> Appajaiah, Anilkumar: Climatic stability of polymer optical fibers (POF) / Anilkumar Appajaiah. - Bremerhaven : Wirtschaftsverl. NW, Verl. für neue Wiss., 2005. - Getr. Zählung [ca. 175 S.]. : Ill., graph. Darst. - (BAM-Dissertationsreihe ; 9)<br> ISBN 3-86509-302-7

This thesis deals with the peroxyoxalate chemiluminescence (POCL) reaction and its application as a detection technique in flow systems for chemical analysis. Particularly, miniaturized flow systems aimed for separation of molecules. In such systems, a high light intensity and a rapid development of the emission are the desired reaction characteristics, for reasons discussed in this text. The work tries to develop an understanding of the chemical processes involved in POCL, with special emphasis to the species favoring or hindering a rapid light evolution. Hence, is the focus placed on the nature of catalysis and the desired properties of substances acting as catalysts in this reaction. Consequently, the scientific papers on which this work is founded includes both systematic stopped-flow studies of catalyst candidates and of the causes for diminished light emission. In addition, multivariate strategies for reaction optimization in practical analysis situations are treated, and the application of the POCL technique to detection of serum-extracted neuroactive steroids, derivatized with fluorescent moieties, is presented. From the experiments in this thesis it is clear nucleophilic catalysts are the most efficient enhancing compounds, which means that they must possess a carefully balanced characteristics of nucleophilicity, leaving group ability, and basicity. The investigations also conclude that the feature of basicity efficiently can be delegated to a non-nucleophilic co-catalyst, which allow the use of nucleophilic catalysts that need to be deprotonated to be active. This thesis also shows the importance of minimizing the amount of competing nucleophiles at the site of reaction to maintain the emission. This implies that also solvents and buffer substances should be carefully chosen not to interfere with the emission process. The most promising combination of catalysts found in this work was 4,5- dichloroimidazole together with 1,2,2,6,6-pentamethylpiperidne. This arrangement was capable of speeding the reaction more than tenfold while increasing the maximum emission intensity by about the same factor.

This thesis covers sampling and analytical procedures for isocyanates (R-NCO) and amines (R-NH2), two kinds of chemicals frequently used in association with the polymeric material polyurethane (PUR). Exposure to isocyanates may result in respiratory disorders and dermal sensitisation, and they are one of the main causes of occupational asthma. Several of the aromatic diamines associated with PUR production are classified as suspected carcinogens. Hence, the presence of these chemicals in different exposure situations must be monitored. In the context of determining isocyanates in air, the methodologies included derivatisation with the reagent di-n-butylamine (DBA) upon collection and subsequent determination using liquid chromatography (LC) and mass spectrometric detection (MS). A user-friendly solvent-free sampler for collection of airborne isocyanates was developed as an alternative to a more cumbersome impinger-filter sampling technique. The combination of the DBA reagent together with MS detection techniques revealed several new exposure situations for isocyanates, such as isocyanic acid during thermal degradation of PUR and urea-based resins. Further, a method for characterising isocyanates in technical products used in the production of PUR was developed. This enabled determination of isocyanates in air for which pure analytical standards are missing. Tandem MS (MS/MS) determination of isocyanates in air below 10-6 of the threshold limit values was achieved. As for the determination of amines, the analytical methods included derivatisation into pentafluoropropionic amide or ethyl carbamate ester derivatives and subsequent MS analysis. Several amines in biological fluids, as markers of exposure for either the amines themselves or the corresponding isocyanates, were determined by LC-MS/MS at amol level. In aqueous extraction solutions of flexible PUR foam products, toluene diamine and related compounds were found. In conclusion, this thesis demonstrates the usefulness of well characterised analytical procedures and techniques for determination of hazardous compounds. Without reliable and robust methodologies there is a risk that exposure levels will be underestimated or, even worse, that relevant compounds will be completely missed.

This thesis presents two hybrid luminescence-based biochemical photosensory microsystems: a CMOS/microfluidic chemiluminescence contact imager, and a CMOS/thin-film fluorescence contact imager. A compact, low-power analog-to-digital converter (ADC) architecture for use in such sensory microsystems is also proposed. Both microsystems are prototyped in a standard 0.35um CMOS technology. The CMOS/microfluidic microsystem integrates a 64x128-pixel CMOS imager and a soft polymer microfluidic network. Circuit techniques are employed to reduce the dark current and circuit noise for low-level light sensitivity. Experimental validation is performed by detecting luminol chemiluminescence and electrochemiluminescence. The CMOS/thin-film microsystem integrates an existing 128x128-pixel CMOS imager and a prefabricated, high-performance optical filter. Experimental validation is performed by detecting human DNA labeled with Cyanine-3 fluorescent dye. The proposed ADC architecture employs a novel digital-to-analog converter with a flexible trade-off between the integration area and the conversion speed. The area savings and good linearity of the DAC are verified by simulations.

This thesis presents two hybrid luminescence-based biochemical photosensory microsystems: a CMOS/microfluidic chemiluminescence contact imager, and a CMOS/thin-film fluorescence contact imager. A compact, low-power analog-to-digital converter (ADC) architecture for use in such sensory microsystems is also proposed. Both microsystems are prototyped in a standard 0.35um CMOS technology. The CMOS/microfluidic microsystem integrates a 64x128-pixel CMOS imager and a soft polymer microfluidic network. Circuit techniques are employed to reduce the dark current and circuit noise for low-level light sensitivity. Experimental validation is performed by detecting luminol chemiluminescence and electrochemiluminescence. The CMOS/thin-film microsystem integrates an existing 128x128-pixel CMOS imager and a prefabricated, high-performance optical filter. Experimental validation is performed by detecting human DNA labeled with Cyanine-3 fluorescent dye. The proposed ADC architecture employs a novel digital-to-analog converter with a flexible trade-off between the integration area and the conversion speed. The area savings and good linearity of the DAC are verified by simulations.

En esta Tesis se aportan nuevos métodos analíticos que demuestran las ventajas que presenta la hibridación de reacciones fotoquímicas y procesos luminiscentes cuando se acoplan como sistema de detección en cromatografía líquida. Se han desarrollado nuevos procedimientos sensibles y selectivos para el análisis de vitaminas del grupo K y del grupo B, sustancias con actividad farmacológica como son los ácidos bisfosfónicos y el antiarrítmico amiodarona y su metabolito desetilamiodarona, ácidos aminopolicarboxílicos y pesticidas del grupo de los N-metilcarbamatos. Todos los métodos propuestos en esta Tesis han sido validados y aplicados al análisis de diferentes muestras reales conteniendo estas especies, tales como preparados farmacéuticos comerciales, fluidos biológicos (suero sanguíneo y orina) y muestras de interés medioambiental (aguas, frutas, verduras, etc.), obteniendo en todos los casos excelentes resultados analíticos. / In this Thesis new analytical methods have been developed for the determination of K and B vitamins, substances with pharmacological activity such as bisphosphonic acids and the antiarrhythmic drug amiodarone and its metabolite desethylamiodarone, aminopolycarboxylic acids and N-methylcarbamate pesticides by high-performance liquid chromatography (HPLC) coupled with post-column photochemical reactions and chemiluminescent or fluorimetric detection.All proposed methods have been successfully validated and applied to the determination of these compounds in different types of environmental and biological samples

Turbulent combustion processes are inherently unsteady and, thus, a source of acoustic radiation, which occurs due to the unsteady expansion of reacting gases. While prior studies have extensively characterized the total sound power radiated by turbulent flames, their spectral characteristics are not well understood. The objective of this research work is to measure the flow and acoustic properties of an open turbulent premixed jet flame and explain the spectral trends of combustion noise. The flame dynamics were characterized using high speed chemiluminescence images of the flame. A model based on the solution of the wave equation with unsteady heat release as the source was developed and was used to relate the measured chemiluminescence fluctuations to its acoustic emission. Acoustic measurements were performed in an anechoic environment for several burner diameters, flow velocities, turbulence intensities, fuels, and equivalence ratios. The acoustic emissions are shown to be characterized by four parameters: peak frequency (Fpeak), low frequency slope (beta), high frequency slope (alpha) and Overall Sound Pressure Level (OASPL). The peak frequency (Fpeak) is characterized by a Strouhal number based on the mean velocity and a flame length. The transfer function between the acoustic spectrum and the spectrum of heat release fluctuations has an f^2 dependence at low frequencies, while it converged to a constant value at high frequencies. Furthermore, the OASPL was found to be characterized by (Fpeak mfH)^2, which resembles the source term in the wave equation.

ABSTRACT DESIGN, SYNTHESIS AND ELECTROPOLYMERIZATION OF A NEW CHEMILUMINESCENT TERTHIENYL SYSTEM Atilgan, Nurdan M.Sc. Department of Chemistry Supervisor: Prof. Dr. Ahmet M. &Ouml / nal Co-Supervisor: Assist. Prof. Dr. Atilla Cihaner September 2008, 57 pages A novel monomer, possessing chemiluminescence properties, 5,7-di-ethylenedioxythiophen-2-yl-2,3-dihydro-thieno[3,4-d]pyridazine-1,4-dione (ETE-Lum) was synthesized. Chemiluminescence properties of ETE-Lum were investigated in alkaline water solution in the presence of H2O2 and this reaction was catalyzed by Fe+3 ion and blood. This study submits a new opportunity to investigate forensic and analytical application instead of 5-amino-2,3-dihydro-1,4-phthalazine-dione (luminol). Response of other metalic cations was also investigated under the same reaction conditions. Electrochemical properties of ETE-Lum were studied in 0.1 M acetonitrile/tetrabutylammonium perchlorate solvent system containing BF3-Et2O and also in neat BF3-Et2O solution. In addition, the corresponding polymer film of ETE-Lum (PETE-Lum) was synthesized successfully via repetitive cycling by cyclic voltammetry and its electrochemical properties were investigated in a monomer-free electrolyte solution. Spectroelectrochemical behavior of the polymer film on indium tin oxide working electrode was also investigated by recording the electronic absorption spectra, in-situ, in monomer-free electrolyte solution at different potentials. Furthermore, spectroelectrochemical studies revealed that PETE-Lum had an electronic band gap of 1.66 eV. The results of electrochemical and electroluminesence measurements indicated that chemiluminecent unit of monomer was protected during polymerization. In addition, PETE-Lum film was found to be electrochemiluminescence active, maintaining its activitiy over 1000 cycles.

Supramolecular chemists can be thought of as architects, who combine individual non-covalently bonded molecular building blocks, designed to be held together by intermolecular forces to create functional architectures. Perhaps the most important assets of a supramolecular chemist, however, are imagination and creativity, which have given rise to a wide range of beautiful and functional systems. For years, analytical chemistry has taken advantage of supramolecular assemblies in the development of new analytical methods. The role of synthetic supramolecular chemistry has proven to be a key component in this multidisciplinary research. As such, the demand for synthetic receptors is rapidly increasing within the analytical sciences. The field “supramolecular analytical chemistry” involves analytical applications of synthetic organic and inorganic chemical structures that display molecular recognition properties and self-assembly but also signal these events. Chapter 1 presents an introduction to the background literature relevant to the central themes of the research presented in this thesis. The nonthermal production of visible light by a chemical reaction leads to the term “cool light”, and the process is called chemiluminescence. Although chemiluminescent reactions are not rare, the production of “cool light” holds such fascination for both chemists and nonchemists that demonstrations of chemiluminescent reactions are always well received. A glow assay technology for the detection of a chemical warfare simulant is presented in Chapter 2, which is based on modulating the peroxyoxalate chemiluminescence pathway by way of utilizing an oximate super nucleophile that gives an off-on glow response. As an alternative to highly analyte-specific synthetic receptors, trends in chemical sensing have shifted to the design of new materials and devices that rely on a series of chemo- or biosensors. The research relevant to Chapter 3 focuses on investigating the use of a single receptor, for sensing two different analytes; thiols and metal ions, utilizing a squaraine as the receptor in a sensor array format. The data is interpreted with principal component analysis. Finally Chapter 4 discusses an attempt to design and synthesize a chemosensor based on the luminophore-spacer-receptor format by incorporating the two concepts photoinduced electron transfer and peroxyoxalate chemiluminescence. / text

This dissertation describes the assessment and use of carbon optically transparent electrodes (C-OTEs) based on pyrolyzed photoresist films (PPFs) as a platform for spectroelectrochemical investigations. C-OTEs are examined for use in UV-Vis spectroelectrochemistry and electrogenerated chemiluminescence and compared to non-transparent glassy carbon (GC) and the conventional transparent electrode indium tin oxide (ITO). Chapter 1 provides a general overview of transparent electrodes, carbon electrodes, and spectroelectrochemistry. Chapter 2 details a UV-Vis spectroelectrochemical investigation of electrogenerated graphitic oxides (EGO) on the surface of the C-OTE in the presence of KCl. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectroscopy are used to determine EGO composition. Several supporting electrolytes are investigated to determine the mechanism of EGO formation. Chapter 3 details experiments to electrochemically access the exciton emission from self-assembled double-walled tubular J-aggregates via electrogenerated chemiluminescence (ECL). Optimization of ECL intensity with respect to the coreactant concentration and the supporting electrolyte pH is performed on opaque glassy carbon electrodes. ECL and fluorescence spectra are compared, and C-OTEs are utilized to determine the source of disagreement between the spectra. Chapter 4 describes the preparation and characterization (i.e. transparency, thickness, sheet resistance, rms roughness, and electroactive surface area) of C-OTEs and explores C-OTEs for general use in ECL under a variety of conditions. Simultaneous cyclic voltammograms and ECL transients are obtained for three thicknesses of PPFs and compared to non-transparent GC and the conventional transparent electrode ITO in both front face and transmission electrode cell geometries. Despite positive potential shifts in oxidation and ECL peaks, attributed to the internal resistance of the PPFs that result from their nanoscale thickness, the PPFs display similar ECL activity to GC, including the low oxidation potential observed for amine coreactants on hydrophobic electrodes. Overall, C-OTEs are promising electrodes for spectroelectrochemical applications because they yield higher ECL than ITO in both oxidative-reductive and reductive-oxidative ECL modes, are more stable in alkaline solutions, display a wide potential window of stability, and have tunable transparency for more efficient detection of light in the transmission cell geometry. Future directions for this research are discussed in Chapter 5, which outlines several approaches to designing and improving spectroelectrochemical sensors. / text