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Développement d’un substrat SPRi/SERS pour des applications en détection moléculaire / Development of an SPRi / SERS substrate for molecular detection applications.Gillibert, Raymond 31 May 2017 (has links)
Dans cette thèse, nous décrivons sommairement les techniques utilisées qui sont l’imagerie parrésonance plasmon de surface (SPRi) et la diffusion Raman exaltée de surface (SERS). Le butprincipal du projet Piranex dans lequel la thèse s’inscrit consiste au développement d’une biopucenanostructurée bimodale permettant le couplage des deux techniques SPRi et SERS. Cettebiopuce est constituée d’un film d’or par-dessus lequel nous avons déposé un réseau carré denanocylindres en or. Un ensemble d’études ont été effectuées pour caractériser ses propriétésplasmoniques du biocapteur afin d’en optimiser le signal SERS. Nous avons ainsi constaté quel’émission du signal était fortement anisotrope, dus à l’excitation du Mode de Bragg et que lechamp proche était principalement exalté sur les bords de la nanostructure. Les propriétés furentégalement comparées avec celles de réseaux identiques déposés directement sur un substrat diélectrique.Par la suite un ensemble d’études plasmoniques et SERS ont été effectuées pourl’aluminium, autre matériaux plasmonique d’intérêt. Enfin, un protocole de détection par SERSde l’ochratoxine basé sur un aptamère fut développé et a permis la détection de l’ochratoxine dès10 pM, bien en dessous de la limite autorisée par les organismes de régulation en agroalimentaire. / In this thesis, we briefly describe the techniques used, which are surface plasmon resonanceimaging (SPRi) and surface enhanced Raman scattering (SERS). The main goal of the Piranexproject in which the thesis is based is the development of a bimodal nanostructured biochipallowing the coupling of the two techniques SPRi and SERS. This bio-chip consists of a goldfilm over which we have deposited a square array of gold nanocylinders. A set of studies hasbeen carried out to characterize plasmonic properties of the biosensor in order to optimize theSERS signal. We have thus found that the emission of the signal was strongly anisotropic, due tothe excitation of the Bragg Mode and that the near field was mainly enhanced on the edges of thenanostructure. The properties were also compared with those of identical gratings depositeddirectly on a dielectric substrate. Subsequently a set of plasmonic and SERS studies were carriedout for aluminum, other plasmonic materials of interest. Finally, a detection protocol by SERS ofochratoxin based on an aptamer was developed and allowed the detection of ochratoxin with adetection threshold of 10 pM, well below the limit allowed by food regulatory agencies
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Alkyne-Functionalized Cyclooctyne on Si(001): Reactivity Studies and Surface Bonding from an Energy Decomposition Analysis PerspectivePieck, Fabian, Tonner-Zech, Ralf 05 May 2023 (has links)
The reactivity and bonding of an ethinyl-functionalized cyclooctyne on Si(001) is studied by means of density functional theory. This system is promising for the organic functionalization of semiconductors. Singly bonded adsorption structures are obtained by [2 + 2] cycloaddition reactions of the cyclooctyne or ethinyl group with the Si(001) surface. A thermodynamic preference for adsorption with the cyclooctyne group in the on-top position is found and traced back to minimal structural deformation of the adsorbate and surface with the help of energy decomposition analysis for extended systems (pEDA). Starting from singly bonded structures, a plethora of reaction paths describing conformer changes and consecutive reactions with the surface are discussed. Strongly exothermic and exergonic reactions to doubly bonded structures are presented, while small reaction barriers highlight the high reactivity of the studied organic molecule on the Si(001) surface. Dynamic aspects of the competitive bonding of the functional groups are addressed by ab initio molecular dynamics calculations. Several trajectories for the doubly bonded structures are obtained in agreement with calculations using the nudged elastic band approach. However, our findings disagree with the experimental observations of selective adsorption by the cyclooctyne moiety, which is critically discussed.
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Stoffübertragung beim SpritzgießenHärtig, Thomas 28 February 2013 (has links)
Das Fügen mehrerer Komponenten während des Spritzgießprozesses wird bei vielen Spritzgießsonderverfahren angewandt. Diese Arbeit beschäftigt sich mit der Verbundbildung zwischen einem kalten Einlegeteil und der einströmenden Kunststoffschmelze beim Spritzgießen, im Folgenden Stoffübertragung genannt. Ein Großteil der Untersuchungen findet an Zweikomponenten-Zugstäben statt, wobei erste und zweite Komponente aus dem gleichen Thermoplast gefertigt werden. Mögliche Einflussfaktoren auf die Verbundfestigkeit werden zunächst im Theorieteil vorgestellt und diskutiert. Eine Auswahl relevanter Prozess- und Materialparameter wird dann in praktischen Versuchen detailliert analysiert. Es wird nach korrelierenden Tendenzen sowohl zwischen unterschiedlichen Verfahren als auch zwischen verschiedenen Kunststoffen gesucht. Mittels statistischer Versuchsplanung werden die Spritzgießparameterkombinationen nach Größe des Einflusses auf die Verbundfestigkeit sortiert. Dies trägt zum Verständnis der bei der Stoffübertragung ablaufenden Grundmechanismen bei. Weiterhin werden die Einflüsse der Prozessparameter auf das neue Verfahren der In-Mold Oberflächenmodifizierung, bei dem ein funktionaler Modifikator während des Spritzgießprozesses übertragen wird, mit den Ergebnissen der Zweikomponenten-Verbundfestigkeit verglichen. Abschließend wird auf die Besonderheiten bei der selektiven Stoffübertragung eingegangen und das neue Verfahren des In-Mold Printing vorgestellt. / The joining of two components by the process of injection molding is state of the art, although adhesion phenomena are not fully understood yet. The formation of bonds between a cold material, which was inserted or applied onto the surface of the cavity before injection molding, and an injected polymer melt is studied in this work. Providing sufficient bond strength, the material is transferred from the surface of the mold to the injection molded part. Possibly influencing factors on the bond strength are first identified, theoretically discussed, later in experiments varied and finally analyzed. Thereby correlating tendencies between different polymers and different in-mold technologies are observed. The relevant material and processing parameters are put in order by their influence on the bond strength using design of experiments. This helps to understand the mechanisms of the formation of bonds. The majority of the experiments is concerned with two component injection molding by measuring the bond strength of two component tensile bars, produced under varying processing conditions. In each case, first and second components are made of the same thermoplastic polymer. The thermal energy of the melt can be used also to initiate chemical reactions. This permits bonding of a thin layer of a functional polymer, which is applied onto the surface of the mold before injecting the melt, to the surface of the molded part. In this way, process-integrated surface modification during injection molding becomes possible. In a further attempt, patterns of paint are printed onto the surface of the mold by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part. Using this new technology of In-Mold Printing, fully finished surface decorated parts can be produced by injection molding.
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