This dissertation details the use of click chemistry to prepare linear and nonlinear polymers containing metal-metal bonds. The incorporation of metal-metal bonds into the polymer simplfies the degradation mechanism, allowing fundamental mechanistic studies of polymer degradation. Click chemistry offered a brand new route to explore the preparation of these useful but intricate metal-metal bond-containing polymers. Chapter I discusses the utility of these types of polymers for mechanistic studies, the preparation of metal dimers with reactive functionalities, and the previous polymerization methods which have been explored. The need for a new polymerization strategy, such as click chemistry, is described. Chapter II explains the preparation of a new metal dimer click synthon, [(η5-C5H4(CH2)3OC(O)(CH2)2C≡CH)Mo(CO)3]2, and the necessary conditions needed to polymerize the synthon using click chemistry. A high molecular weight linear polymer was prepared, suggesting click chemistry is a viable route to nonlinear polymers. Chapter III presents a second novel metal dimer click synthon, [(η5-C5H4(CH2)3N3Mo(CO)3]2, and attempts to use click chemistry to prepare a star polymer containing metal-metal bonds. A small amount of nonlinear polymer was prepared but several reactivity problems were also discovered and addressed. Due to these problems with click chemistry, Chapter IV details a brand new method for preparing asymmetric metal dimers. CpMo(CO)3-Mo(CO)3Cp(CH2)3CH=CH2 is the first reported example of an asymmetric dimer, and (CH3)3CSi(CH3)2O(CH2)3CpMo(CO)3-Mo(CO)3Cp(CH2)3OC(CH3)2OCH3 is the first example of a bifunctional asymmetric dimer. Chapter V describes the synthesis of a different type of metal dimer, (CH3)2Si[(C5H5)Mo(CO)3]2, which is polymerized by thermal ring opening polymerization. The dimer did not polymerize as expected and yielded an interesting polymer which has both Mo-Mo single bonds and Mo≡Mo triple bonds. Finally, Chapter VI provides a summary of the work as well as an honest perspective of using click chemistry to prepare metal-metal bond-containing polymers. This dissertation includes previously published and unpublished co-authored material. / 10000-01-01

In many applications such as beam shaping, mode conversion, and phase encoding it is necessary to alter the spatial phase profile of a beam via a phase mask. Conventional techniques to accomplish this either involve surface relief profiling in thin films such as PMMA or refractive index modulation in bulk photorefractive crystals such as lithium niobate. These materials have been used extensively for the past several decades and perform admirably in low power conditions. However, in high power systems these materials will be destroyed, requiring a new means of producing phase masks. In this dissertation a method for producing robust phase masks in the bulk of photo-thermo-refractive glass is developed and successfully demonstrated. Three main applications of phase masks were studied in detail. The first is mode conversion, where binary phase masks convert a Gaussian beam to higher order modes. The second is beam shaping, where phase masks are used as focusing elements and for optical vortex generation. Near-theoretical conversion efficiency was achieved for all elements in these cases. The third application is aberration analysis and correction. Here the degradation of volume Bragg gratings recorded in an aberrated holographic system was modeled, with the simulations indicating that correcting elements are generally necessary for high-quality production of gratings. Corrective phase masks are designed which can selectively correct one or multiple aberrations of varying magnitudes are shown. A new type of optical element is also developed in which a phase mask is encoded into a transmitting Bragg grating. This technique combines the local phase modulation of a phase mask with the multiplexing ability of transmitting Bragg gratings, allowing for multiple phase masks to be recorded in a single element. These masks may be used at any wavelength iii satisfying the Bragg condition, increasing the useful wavelength regime of a single element by orders of magnitude.

Purpose Intrinsically photosensitive retinal ganglion cells (ipRGCs) express a unique photopigment called melanopsin. Capable of direct phototransduction, the ipRGCs are also influenced by rods and cones via synaptic inputs.  Thus, the photoinput that mediates the pupil light reflex derives from both outer (rods and cones) and inner (melanopsin-mediated) retinal photoreception. This thesis has aimed to develop a pupillometric test that provides quantitative information about the functional status of outer and inner retinal photoreception in healthy eyes and in eyes with retinal degeneration. In addition to regulating the pupil light reflex, the ipRGCs signal light information for the circadian rhythm, thus, these two non-visual physiologic responses to inner retinal photoreception were examined simultaneously. Methods Pupil responses to a long and short wavelength light over a range of intensities (under conditions of light, mesopic and dark adaptation) were recorded using a customized infrared computerized pupillometer. Results were compared for two groups: patients with retinitis pigmentosa and controls. The response function threshold intensity and a half-max intensity was determined from the rod-weighted and cone-weighted pupil responses and correlated to extent of visual loss. The pupil response to light offset was assessed as a measure of direct melanopsin activation. Lastly, pupil responses to red and blue light at equal photo flux were recorded hourly during a 24-hour period and correlated to salivary melatonin concentrations in healthy subjects. Results In normal eyes, the blue light evoked greater pupil responses compared to equiluminant red light. With increasing intensity, pupil contraction became more sustained which was most apparent with the brightest blue light. In patients with retinitis pigmentosa, the pupil responses mediated predominantly by rod and cone activation were significantly reduced compared to controls, (p<0.001) and the relative decrease in their contribution resulted in a greater influence of melanopsin on the post-stimulus response. Even at endstage retinal degeneration, pupil responses that derived predominantly from residual cone activity were detectable. The threshold intensity of the rod-mediated, but not cone-mediated, pupil response was also significantly reduced (p=0.006) in patients and the half-maximal intensity of rods correlated with severity of visual loss (r2=0.7 and p=0.02). In healthy controls, the melanopsin-mediated pupil response demonstrated a circadian modulation whereas the cone-mediated pupil response did not. Conclusion Early and progressive loss of rod function in mild-moderate stages of retinitis pigmentosa is detectable and quantifiable as a progressive loss of pupillary sensitivity to extremely dim blue lights obtained under conditions of dark adaptation. In advanced stages of retinal degeneration, chromatic pupillometry is more sensitive than standard electroretinography for detecting residual levels of rod and especially cone activity. In addition, selective wavelength pupillometry can assess non-visual light-dependent functions. The timing of the post-stimulus pupil response to blue light is in phase with melatonin secretion, suggesting a circadian regulation of this pupil parameter. / Bakgrund Jätteganglieceller (intrinsically photosensitive retinal ganglion cells, ipRGCs) är en klass av fotoreceptorer som utnyttjar ett unikt vitamin-A-baserat fotopigment som kallas melanopsin. Utöver deras direkta ljuskänslighet, mottar ipRGCs stimulerande och hämmande synaptiska signaler från andra fotoreceptorer (tappar och stavar) som därigenom kan modulera aktiviteten hos ipRGCs. Ögats pupillreflex medieras alltså av ljus både via yttre (stavar och tappar) och inre (melanopsin-medierad) retinal fotoreception, och den gemensamma afferenta pupillomotor-signalen leds till den pretectala nucleus olivarius via axoner från ipRGCs. Arbetet i denna avhandling syftar till att utveckla ett kliniskt pupilltest som ger kvantitativ information om yttre och inre retinala fotoreceptorers funktionella status hos friska försökspersoner och patienter med retinal degeneration. Förutom att styra pupillreflexen, skickar ipRGCs även impulser som påverkar kroppens dygnsrytm. Därför ingår även en delstudie i vilken ipRGCs aktivitet studeras genom att avläsa icke-visuella fysiologiska reaktioner på inre retinal fotoreception. Metoder Ljus av lång (röd) respektive kort (blå) våglängd presenterades med stegvis ökad ljusstyrka för att selektivt stimulera stavar, tappar eller melanopsin. Pupillreaktionerna registrerades med en infraröd datoriserad pupillometer och jämfördes mellan friska kontroller och patienter med retinitis pigmentosa. I uppföljande experiment gjordes mer noggranna tester i syfte att isolera aktiveringen av varje ljusmottagande element. Tröskelintensiteten för stav- eller tapp-medierad pupillreaktion bestämdes med linjär regressionsanalys. Reaktionskurvan för stavmedierad pupillreflex kvantifierades (halv-maximal intensitet) och jämfördes med svårighetsgraden av sjukdomen i två familjer med samma sjukdomsframkallande mutation för retinitis pigmentosa. För att undersöka icke-visuella reaktioner på inre fotoreception från ipRGCs, undersöktes pupillreaktion på rött och blått ljus varje timme under en 24-timmarsperiod och korrelerades till melatoninkoncentration i saliv hos friska personer med normal syn. Resultat I normala ögon, gav blått ljus en kraftigare pupillreaktion jämfört med rött ljus av samma ljusstyrka. Med ökande intensitet, blev pupillkontraktionen mer ihållande, vilket var tydligast med starkt blått ljus. Hos patienter med retinitis pigmentosa, var både tapp- och stav-medierad pupillreaktion signifikant reducerad jämfört med kontroller, (p<0,001). Patienter med avancerad sjukdom och icke-reaktivt elektro-retinogram hade fortfarande mätbar pupillreflex, huvudsakligen härrörande från kvarvarande stavaktivitet. I två familjer med retinitis pigmentosa beroende på en enda missense-mutation av NR2E3 genen, var tröskelvärdet för stavmedierad pupillreflex signifikant reducerat (p= 0,006) och korrelerade till sjukdomens svårighetsgrad. Tappmedierad pupillreflex hos dessa patienter skilde sig dock inte signifikant från kontroller, trots att fotopiskt (tapp) elektroretinogram var klart avvikande. Hos friska kontroller visade melanopsinmedierat pupillsvar en dygnsvariation medan tapp-medierat pupillsvar inte gjorde det. Slutsatser Som tillägg till standardundersökningar kan selektiv våglängds-pupillometri (kromatisk pupillometri) vara användbart för utvärdering av funktionen hos stavar och tappar. Denna avhandling visar att tidig och gradvis förlust av stav-funktion i milt-måttligt stadium av retinitis pigmentosa är detekterbar och mätbar som en progressiv förlust av pupillens känslighet för mycket svagt blått ljus, efter mörkeradaptation. I avancerade stadier av retinal degeneration är kromatisk pupillometri känsligare än standardelektroretinografi för att detektera kvarvarande nivåer av stav- och speciellt tapp-aktivitet. Hos unga patienter, där elektroretinografi kan vara tekniskt svårt, är pupillometri en lovande teknik för att värdera yttre retinal fotoreception relaterad till synfunktion. Dessutom kan selektiv våglängdspupillometri ge information om icke-visuella ljusberoende funktioner. Pupillreaktionen på blått ljus varierar med melatoninsekretionen, vilket tyder på en cirkadisk reglering. Ytterligare studier krävs för att undersöka om selektiv våglängds-pupillometri även kan användas i samband med sjukdomar relaterade till störd dygnsrytm, som sömnlöshet och årstidsbunden depression.

Nous avons étudié théoriquement et expérimentalement la formation de réseaux en relief sur des surfaces active ou passive, avec deux types de polymères photosensibles : résine photosensible négative et copolymère azobenzene. Le mécanisme de formation des structures est attribué à l'effet de transport de masse, qui déplace la matière dans des directions opposées dans ces deux matériaux. La technique de fabrication est basée sur l'utilisation de la lithographie par interférence, ce qui a permis de créer des structures grandes et uniformes. Dans le premier cas, des structures passives de surface en relief en 1D et 2D ont été créés sur la résine photosensible négative SU8 grâce à l'effet de rétrécissement durant le processus de réticulation. Dans le second cas, des structures périodiques actives en 1D, 2D et 3D ont été obtenues grâce à la migration des matériaux copolymères DR1/PMMA des régions de forte intensité d’irradiation à celles de faible intensité. L'amplitude de modulation de la structure est optimisée par le contrôle de l'épaisseur du film, de la périodicité de la structure, de la dose d'exposition, et des polarisations des faisceaux laser. Les applications de ces structures pour des lasers DFB à multiples longueurs d'onde, les cristaux photoniques non-Linéaires, et le couplage dans les guides d'ondes ont été discutés. / We have theoretically and experimentally investigated the formation of both active and passive surface relief gratings on two kinds of photosensitive polymers: negative photoresist and azobenzene copolymer. The common mechanism of the structures formation was attributed to mass transport effect, which however pushes the materials in opposite directions in these two materials. The fabrication technique is based on the use of interference lithography, which allowed to create large and uniform structures. In the first case, 1D and 2D passive periodic surface relief structures were created on the negative photoresist SU8 thanks to the shrinkage effect during the crosslinking process. In the second case, 1D, 2D and 3D active periodic structures have been obtained thanks to the movement of DR1/PMMA copolymer materials from regions of high intensity to those of low intensity irradiation. The modulation amplitude of structures is optimized by controlling the film thickness, the structure periodicity, the exposure dosage, and the polarizations of interference laser beams. Applications of these structures for multiple wavelength DFB laser, nonlinear photonic crystals, and waveguide coupling have been discussed.

To enable fast and reliable processors, advances must be made in the interconnections on the printed circuit board and in the interconnections from the chip to the printed circuit board. Processing techniques have been demonstrated to fabricate a copper-clad encapsulated air dielectric layer to enable low loss off-chip electrical signal lines using sacrificial polymers and the three dimensional patterning capabilities of imprint lithography. The inclusion of an air gap can eliminate the dielectric loss allowing the signal to propagate over longer lengths. Additionally, the low dielectric constant of air lowers the loss contributions from the conductor and increases the signal propagation velocity reducing delay. The metal shielding could minimize the crosstalk noise and radiation losses that are significant at high frequencies. The three dimensional patterning capabilities of imprint lithography fabricated curved structures and rounded terminations which can reduce reflections at discontinuities. Furthermore, imprint lithography also created planarized surfaces which simplified the buildup process. Since imprint lithography, only uses temperature and pressure to make a pattern it is an inexpensive and simple process advancement. The metal-clad encapsulated air dielectric structures were fabricated in a comparable number of registration steps to traditional transmission lines. Implementation of all copper chip to substrate interconnects would provide high conductivity electrical connections, resistance to electromigration while avoiding formation of brittle intermetallics. High aspect ratio polymer molds for copper electroplating interconnects could enable improved integrated circuit electrical performance. The properties of a new aqueous base develop, negative-tone photosensitive polynorbornene polymer have been characterized to develop mechanically compliant all copper connections between the chip and printed circuit board. High aspect ratio features of 7:1 (height:width) were produced in 70 ìm thick films in a single coat with straight side-wall profiles and high fidelity. The polymer films studied had a contrast of 11.6 and a low absorption coefficient. To evaluate the polymer's suitability to microelectronics applications, epoxy cross-linking reactions were studied as a function of processing condition through Fourier transform infrared spectroscopy, nano-indentation, and dielectric measurements. The fully cross-linked films had an elastic modulus of 2.9 GPa and hardness of 0.18 GPa which can improve the mechanical compliance of the copper interconnections. A photo-imprint lithography process was developed to improve the photo-patterning of the polynorbornene polymer for high aspect ratio hollow structures. A shallow photo-imprint stamp was developed to physically displace material in the polymer core. Since the imprint stamp displaces material in the area of the feature, the effective film thickness is reduced compared to the bulk film. The reduction in film height reduced the effects of scattering in the core and also facilitated transport of developer within the core. The photo-imprint lithography process resulted in high aspect ratio hollow core pillars that exceeded optical resolution capabilities for comparable feature sizes.

Des matériaux polymères photosensibles ont été élaborés selon trois méthodes différentes : la synthèse de réseaux, la technique de Langmuir-Blodgett et le spin-coating. Les modulations des propriétés de mouillage induites par stimulus lumineux ont été étudiées par mesures dynamiques d'angle de contact et corrélées aux processus photochimiques mis en jeu, isomérisation trans→cis et/ou dimérisation des groupements photosensibles.Deux types de polymères photosensibles ont été synthétisés, un polymère cellulosique portant des groupements cinnamate et des copolymères associant les propriétés photo-induites de groupements azobenzène aux propriétés anti-adhésives de monomères fluorés. La densité de groupements photosensibles a été variée soit par modification de la densité de greffage des cinnamates sur le polymère cellulosique, soit par changement de la composition du copolymère. Les processus photochimiques induits sous irradiation UV ont été étudiés en solution puis au sein des différents matériaux. Après caractérisation des deux types de films élaborés avec ces polymères, films de Langmuir-Blodgett et films spin-coatés, et des matériaux réticulés, les propriétés de mouillage de l'eau et du diiodométhane ont été étudiées avant et après irradiation UV. Les résultats obtenus montrent que la méthode d'élaboration des surfaces et l'environnement des groupements photosensibles jouent un rôle significatif sur les processus photochimiques mis en jeu et les modulations des propriétés de mouillage associées. / We report on the elaboration of photosensitive polymer materials using three different methods : synthesis of polymer networks, the Langmuir-Blodgett technique and the spin-coating. The modulation of the photo-induced wetting properties has been studied by dynamic contact angle measurements and correlated to the photochemical processes, trans→cis isomerization and/or dimerization of the photosensitive groups.Two different photosensitive polymers have been synthesized, a cellulosic polymer modified by cinnamate groups and copolymers which combine the photo-induced properties of azobenzene groups and the anti-adhesive properties of fluorinated monomers. The density of photosensitive groups was varied by changing either the grafting density of cinnamate groups in the cellulosic polymer, or the composition of the copolymer. The photochemical processes of these photosensitive polymers were characterized in solution as well as in the different films or materials. After characterization of the two types of films prepared with these polymers, Langmuir-Blodgett and spin-coated films, and of the crosslinked materials, the wetting properties of water and diiodomethane were studied before and after UV irradiation. The results show that the sample preparation and the photosensitive groups environment play a significant role in the involved photochemical processes and the associated wetting properties.

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Orientador: Lucila Helena Deliesposte Cescato / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-15T19:36:27Z (GMT). No. of bitstreams: 1 Avila_LuisFernandode_D.pdf: 1824665 bytes, checksum: 6cab44933ac386ebd3097bd193d85e0f (MD5) Previous issue date: 2010 / Resumo: Materiais fotossensíveis são materiais que sofrem alterações físico-químicas quando expostos à luz de comprimento de onda apropriado. A gama de aplicações para estes materiais é enorme, entre elas as que apresentam maiores exigências em termos do próprio material são as aplicações em armazenagem de informação e imagens. Para avaliar o potencial de um material para uma dada aplicação é necessário entender os mecanismos fotossensíveis envolvidos assim como caracterizar suas propriedades, tais como: sensibilidade espectral, modulação óptica máxima, reversibilidade, estabilidade térmica, etc. Nesta tese de doutorado foi proposto e demonstrado um método para processar os sinais de auto-difração que, além de permitir a medida simultânea e independente das modulações de índice de refração e de coeficiente de absorção, nos permite medir a evolução temporal das modulações e a constante cinética das reações fotossensíveis. Esta técnica foi utilizada para estudar três tipos de materiais fotossensíveis: fotorresinas positivas (SC 1827 da Shipley), fotorresinas negativas (SU-8 da Microchem) e vidros calcogenetos (em particular composições com Sulfeto de Antimônio). As medidas foram realizadas utilizando-se dois interferômetros diferentes: um com óptica para o visível e outro para o ultravioleta. Além disso, foi observada uma modulação de elétrons secundários nas imagens de microscopia eletrônica de amostras de fotorresinas negativas SU8 expostas holograficamente / Abstract: Photosensitive materials are materials that change their optical properties when exposed to light of appropriate wavelength. The range of applications of such materials is very wide. Among these applications the storage of images and information is that present higher requirements in terms of the material itself. To evaluate the potential of a material for a given application it is necessary to understand the mechanisms involved as well as to characterize their photosensitive properties such as spectral sensitivity, maximum optical modulation, reversibility, thermal stability, etc. In this thesis we propose and demonstrate a method for processing the selfdiffraction the signals that allows the simultaneous and independent measurement of the modulations of refractive index and absorption coefficient as well as to measure the temporal evolution of such modulations and their corresponding kinetic constant of the photo-reactions. This technique was employed to study three types of photosensitive materials: positive photoresist (SC 1827 from Shipley), negative photoresist (Microchem SU-8) and chalcogenide glasses (in particular compositions with Antimony Sulfide). Measurements were performed using two different interferometers, one with optics for the visible and one for the ultra-violet. Moreover, a modulation of secondary electrons was observed in the electronic microscopy images of the SU8 negative photoresist samples exposed holographically / Doutorado / Ótica / Doutor em Ciências

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-19T14:55:58Z No. of bitstreams: 1 jeffersondasilvamartins.pdf: 25462005 bytes, checksum: 953964ec162955054c296ec7a3712b33 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-20T12:26:53Z (GMT) No. of bitstreams: 1 jeffersondasilvamartins.pdf: 25462005 bytes, checksum: 953964ec162955054c296ec7a3712b33 (MD5) / Made available in DSpace on 2017-04-20T12:26:53Z (GMT). No. of bitstreams: 1 jeffersondasilvamartins.pdf: 25462005 bytes, checksum: 953964ec162955054c296ec7a3712b33 (MD5) Previous issue date: 2013-07-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fotorresinas são exemplos de materiais fotossensíveis largamente empregadas em processos litográficos em microeletrônica e em óptica para a fabricação de componentes de relevo. As fotorresinas são usadas como máscaras para transferência de padrões geométricos para fabricação de mais de 95% dos circuitos integrados utilizados em microeletrônica. Em óptica, as fotorresinas são usadas na construção de estruturas periódicas com propriedades ópticas difrativas. Uma importante técnica de caracterização dessas fotorresinas é a espectrometria de massa. Essa ferramenta espectrométrica é muito poderosa no estudo de superfícies, processos de controle de crescimento de filmes em microeletrônica e em outras ramificações da ciência. Nesse contexto, nesta dissertação de mestrado são apresentados os resultados dos processos de degradação da fotorresina AZ-1518, devido a exposição à radiação ultravioleta. Os produtos da degradação ocasionados pela ação da radiação ultravioleta é avaliada por espectrometria de massa por tempo de voo usando ionização e dessorção a laser (LDI). A cinética química das fotorresinas, de acordo com o método proposto por Dill, mostra que a taxa de variação temporal da concentração do composto fotoativo é proporcional à intensidade da luz incidente. Este parâmetro é medido usando o processo de exposição com o espectro típico de uma lâmpada de vapor de mercúrio (comprimentos de onda de 365, 405 e 436 nm). Em virtude dos resultados apresentados, mostra-se que a técnica de ionização e dessorção a laser é capaz de identificar as modificações moleculares na fotorresina, devido à exposição de luz ultravioleta apresentando diferenças nas intensidades relativas dos espectros de massa das amostras expostas e não expostas à radiação ultravioleta. Devido às variações nas intensidades relativas dos espectros de massa das amostras que receberam diferentes energia de exposição, foi possível caracterizar a cinética química da fotorresina AZ-1518. Esse resultado mostra que a técnica de ionização e dessorção a laser é adequada para estudar a cinética química de materiais fotossensíveis e obter o parâmetro de Dill das fotorresinas positivas. / Positive photoresists are photosensitive materials widely used in lithographic processes in microelectronics and optic for component relief manufacturing. The photoresists are used as masks for transferring of geometric patterns to produce more than 95% of the integrated circuits employed in microelectronics. In optics, the photoresists are used in the fabrication of periodic structures with diffractive optical properties. An important technique of the characterization of such photoresists is the mass spectrometry. This spectrosmetry tool is very powerful in the study of surfaces, control processes of film growth in microelectronics and other branching of science. In this context, this work presents results of the degradation processes of the AZ-1518 photoresist due to exposure to ultraviolet radiation. The degradation products occasioned by the action of ultraviolet radiation is analyzed by time-of-flight mass spectrometry using laser desorption ionization (LDI). The chemical kinetics of photoresist, according to the method proposed by Dill, shows that the rate of temporal variation of the concentration of photoactive compound is proportional to the intensity of incident light. This parameter is measured using the exposure to a typical mercury arc lamp spectrum (365, 405 and 436 nm wavelengths). In view of the results presented, takes us up to believe that the technique of laser desorption ionization is able to identify the molecular modifications in the photoresist due to exposure to ultraviolet light showing differences in the relative intensities of the mass spectra of the samples unexposed and exposed to ultraviolet radiation. Because of the variations in the relative intensities of the mass spectra of the samples that received different exposure energies, it was possible to characterize the chemical kinetics of the AZ-1518 photoresist. This result shows that the technique of laser desorption ionization is appropriate for the study of chemical kinetics of photosensitive materials and to obtain the Dill parameter of positive photoresists.