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Submitted by Mariele Seco null (mariele.seco@gmail.com) on 2017-09-24T22:14:55Z No. of bitstreams: 1 Dissertação_SECOMariele.pdf: 5743463 bytes, checksum: de561ce070d8e87818e8d3b4f24b1430 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-27T19:59:58Z (GMT) No. of bitstreams: 1 seco_m_me_sjrp.pdf: 5743463 bytes, checksum: de561ce070d8e87818e8d3b4f24b1430 (MD5) / Made available in DSpace on 2017-09-27T19:59:58Z (GMT). No. of bitstreams: 1 seco_m_me_sjrp.pdf: 5743463 bytes, checksum: de561ce070d8e87818e8d3b4f24b1430 (MD5) Previous issue date: 2017-09-04 / Esta pesquisa volta-se ao estudo dos aspectos culturais presentes nas expressões idiomáticas relacionadas a gastronomismos (EIGs) em português do Brasil. Correspondentes idiomáticos em francês da França são sugeridos para essas expressões constituídas por nomes de alimentos, com o fim de evidenciar que, por vezes, as diferentes culturas conferem ao léxico valores particulares a um povo, as chamadas cargas culturais partilhadas (CCPs), conceito criado por Galisson (1988). As expressões idiomáticas (EIs), entendidas como lexias complexas, indecomponíveis, conotativas e cristalizadas em um idioma pela tradição cultural (XATARA, 1998), podem gerar dificuldades na intercompreensão dos estrangeiros que não partilham de uma mesma cultura e, portanto, que não reconhecem suas referências extralinguísticas. Com isso, defende-se a difusão dos aspectos e das cargas culturais que essas expressões encerram em dicionários especiais bilíngues para aprendizes de língua estrangeira, que sejam úteis também para tradutores e demais consulentes. A hipótese delineada é a de que, uma vez que a cultura se revela nessas estruturas, cada povo apresenta um repertório específico de EIs, baseado em suas visões de mundo e, como consequência, as EIs correspondentes em outras línguas apresentariam diferenças substanciais na sua constituição e, por vezes, no uso. Contudo, a análise de um inventário de 111 EIGs em português do Brasil e 100 correspondentes idiomáticos em francês da França, resulta que, ao contrário do que se pensava, muitas EIs correspondentes apresentam semelhanças sintáticas e semânticas, fazendo uso, algumas vezes, dos mesmos referentes, porém, sustenta-se que as diferenças culturais ainda podem ser percebidas. Muitas vezes, ainda que o referente seja o mesmo, a CCP varia de uma língua para outra, podendo gerar incompreensão ou mal-entendidos quanto à significação das EIs. Para realização deste estudo, um banco de dados, o BD-CULTEIG, constituiu-se em uma primeira etapa, a fim de gerar um produto fraseográfico de caráter cultural, centrado nas expressões idiomáticas relacionadas a gastronomismos. A proposta do banco de dados não visa criar tão somente uma ferramenta de tradução, mas uma obra que auxilie na compreensão das EIs, com suporte à compreensão da cultura do outro, possibilitando sanar possíveis dúvidas quanto ao uso adequado dessas estruturas. Nele estão contidas as 111 EIGs do português do Brasil e 100 correspondentes em francês da França, seguidas de EIs sinônimas e variantes nas duas línguas, definição, exemplos-ocorrências coletados na web como corpus (Kilgarriff e Greffenstette, 2003), aspectos culturais e outras observações, que consistem em informações, quando necessárias, acerca do conteúdo semântico e uso dos idiomatismos. / This research is oriented to the study of cultural aspects contained in idioms related to gastronomy (EIGs) in Brazilian Portuguese. Idiomatic correspondences in French of France are suggested for these expressions composed by food names to highlight that, at times, different cultures give the lexicon particular values to a people, the so-called shared cultural content (CCPs), a concept created by Galisson (1988). Idioms (EIs), understood as complex lexias, indecomposable, connotative and crystallized in a language by cultural tradition (XATARA, 1998), can generate difficulty in inter-comprehension among foreigners that don’t share the same culture and therefore don’t recognize their extralinguistic references. Thereby, we defend the dissemination of aspects and cultural heritage that these expressions enclose in special bilingual dictionaries for foreign language learners, that can also be useful for translators and other consultants. The outlined hypothesis is that once the culture reveals itself in these structures, each people presents a specific repertoire of idioms, based on their perception of the world and, as consequence, the correspondent idioms in other languages would present substantial differences in their constitution and, at times, in their usage. However, the analysis of an inventory composed by 111 gastronomy idioms in Brazilian Portuguese and 100 idiomatic correspondences in French of France, contrary to what was thought, results that a lot of idioms present syntactic and semantic similarities, using sometimes the same references, but with cultural differences that can still be noticed. Many times, even if the reference is the same, the shared cultural content varies from a language to another and can result in incomprehension or misunderstandings concerning the meanings of the idioms. To perform this study, a database, the BD-CULTEIG, was constituted in a first phase to generate a phrase product with cultural character, centered in idioms related to gastronomy. The proposal of the database is not only to create a translation tool but a work that helps understanding idioms, with support for comprehension of other cultures, allowing it to answer any doubts related to the appropriate use of these structures. It contains the 111 idioms in Brazilian Portuguese and 100 correspondences in French of France, followed by synonyms and variant idioms in both languages, definition, examples of occurrence collected on the web as corpus (Kilgarriff e Greffenstette, 2003), cultural aspects and other observations consisting of information, when needed, about the semantic content and idioms usage.

De nos jours, la galvanisation continue par immersion à chaud est largement utilisée dans les structures métalliques pour protéger les aciers contre la corrosion. Le zinc offre une barrière protectrice grâce à la formation d'un oxyde de surface et d'un effet de protection sacrificielle. Cependant, les procédés de fabrication de la structure ou les assemblages mécaniques par déformation plastique peuvent créer des dommages affectant les performances de corrosion du revêtement.L’objectif de ce travail était d’étudier la durabilité, en environnement agressif, par des essais d’immersion et en enceinte climatique, de revêtements galvanisés déformés à la suite d’une mise en forme. Trois revêtements différents ont été choisis. Un revêtement de zinc utilisé comme référence, un revêtement Zn-Al-Mg dans lequel l’ajout de magnésium et d’aluminium permet une meilleure tenue à la corrosion et enfin un revêtement Zn-55Al choisi pour sa très bonne durabilité en environnement agressif en raison de la quantité importante d’aluminium présente dans sa composition. / Nowadays continuous hot-dip galvanizing is widely used in metallic structures to protect steels against corrosion. Zinc provides a protective barrier thanks to the for-mation of a surface oxide and a sacrificial protection effect. However, structure manufacturing processes or mechanical assemblies by plastic deformation can create damage affecting the corrosion performance of the coating.The objective of the present work is to study changes of corrosion resistance induced by plastic deformation using immersion and climatic chamber tests. Three different coatings were chosen. A zinc coating used as a reference, a Zn-Al-Mg coating in which the addition of magnesium and aluminum allows a better resistance to corrosion and finally a Zn-55Al coating chosen for its very good durability in aggressive environment in Because of the large amount of aluminum present in its composition.

In the initial stage, the sample preparation was done by using the techniques of Anodic etching and anodic forming processes where a repeated trial and error method of sample preparation headed towards making out a suitable sample set for characterization. After this step, the set of 2 different industrial samples were introduced and anodic oxide forming process was carried out in different electrolytes.    In the sample preparations, 4 different electrolytes were used 15% wt. Ammonium Adiphate, 1.5% wt. Ammonium Phosphate, 7% wt. Boric acid and 15% Penta Borate at different stages for performing the anodic oxide forming process. Minimum forming voltages of 20V to a maximum of 100V was employed in the sample preparation and to overcome the waiting time in forming the etched samples a higher current of 0.5A was used.   After the samples preparation, Electrochemical Impedance spectroscopy was used as a tool for characterising the various groups of samples and for observing the micro structures of various samples, they were fractured and the observed on the cross section by SEM.   After the analysis of the etched samples was made, an attempt to compare the results of the data of these samples to that of the 2 set of industrial samples was made and found that the resultant data wasn’t stable enough to characterize since huge scattering were occurring and whereby the simulation of the CPE circuit for the chosen circuit in the analysis was not possible.   Under the analysis, a randomly chosen industrial sample was also used and the resultant data was utilised in understanding the response of the system to different electrolytes. / Sammanfattning   Avhandlingsarbetet har genomförts på KEMET AB i samarbete med yttekniklaboratoriet vid JTH i syfte att karakterisera den etsade anodiska aluminiumfolien som grundprov med anodisering och etsning för ytbehandling.   I inledningsskedet gjordes provberedningen med användning av teknikerna för anodisk etsning och anodbildande processer där en upprepad provnings- och felmetod för provberedning ledde ut mot att utarbeta en lämplig provuppsättning med avseende på karakterisering. Efter detta steg infördes uppsättningen av 2 olika industriella prover och anodoxidbildande process utfördes i olika elektrolyter.   I provpreparaten användes 4 olika elektrolyter 15 % vikt Ammoniumadiphat, 1,5 vikt% Ammoniumfosfat, 7 vikt% Borsyra och 15 % Penta-borat vid olika steg för utförande av anodoxidbildningsförfarandet. Minimala formningsspänningar på 20V till ett maximum av 100V användes i provframställningen och för att övervinna väntetiden vid bildning av de etsade proven användes en högre ström av 0,5A.   Efter provberedningen användes elektrokemisk impedansspektroskopi som ett verktyg för att karakterisera de olika grupperna av prover och för att observera mikrostrukturerna i olika prover, de bröts och de observerades i tvärsnittet av SEM.   Efter att analysen av de etsade proverna gjordes ett försök att jämföra resultaten av data från dessa prover till den för de två uppsättningarna av industriella prover. Det är konstaterat att de resulterande data inte var stabila nog att karakterisera eftersom stor spridning inträffade och varigenom simuleringen av CPE-kretsen för den valda kretsen i analysen inte var möjlig.   Under analysen användes också ett slumpmässigt valt industriellt prov och de resulterande data användes för att förstå systemets respons till olika elektrolyter.

Le sujet de thèse concerne l’analyse et la prédiction de la corrosion des renforts métalliques exposés dans des environnements représentatifs. Dans cette étude, le système va se complexifier en commençant à partir du renfort métallique délaitonné (acier perlitique) en passant par le renfort métallique laitonné (couche de laiton) pour finir avec le renfort métallique sulfuré (couche de sulfures). Cette approche permet de comprendre pas à pas les phénomènes de corrosion ainsi que l’interaction entre les différentes couches. Les matériaux de l’étude sont caractérisés au départ par des techniques de microscopies (MEB-EBSD, MET) et d’analyses de surface (XPS, Auger). Ces informations microstructurales et de composition chimique sont essentielles pour l’interprétation des essais de corrosion. Les essais électrochimiques sont ensuite réalisés dans 0,1M NaCl pour observer et quantifier le comportement en corrosion des trois types de renforts de l’étude. La quantification est un élément important pour établir des modèles prédictifs de corrosion. Deux types de techniques électrochimiques sont utilisés, les mesures à l’échelle globale (Voltampérométrie, Impédance électrochimique, couplage galvanique…) et les mesures à l’échelle locale (microcellule). Les essais à l’échelle locale sont directement reliés aux cartographies EBSD grâce à la microcellule. Un lien direct microstructure-corrosion est donc établi. A partir des essais électrochimiques, des analyses de solutions (SAA, ICP…) ainsi que des mesures de pH localisées sont réalisés pour quantifier les espèces passant en solution. Ces résultats sont des données d’entrée pour définir un milieu représentatif. De nouveaux essais électrochimiques sont enfin effectués dans le milieu représentatif pour étudier l’impact de ce nouveau milieu sur la corrosion des renforts métalliques. / This work deals with analysis and corrosion prediction of steel cords exposed in representative environments. In this study, the system will become more and more complex starting from “délaitonné” metal reinforcement (perlitic) via the brass metal reinforcement (brass layer) to finish with the metal reinforcement sulfide (sulfide layer). This approach allows you to understand step by step corrosion phenomena and the interaction between different layers. Materials of the study are first characterized by microscopy techniques (SEM-EBSD, TEM) and surface analysis (XPS, Auger). These microstructural informations and chemical composition are essential for interpretation of corrosion tests. Electrochemical tests are worked out in 0,1M NaCl to observe and quantify corrosion behavior of the three kind of steel cords. Quantification is a significant element to establish predictive corrosion models. Two electrochemical techniques are used, measurements at global scale (voltammetry, electrochemical impedance, galvanic coupling ...) and locally measurements (microcell). Measurements at the local scale are directly linked to EBSD maps thanks to the microcell. A direct link microstructure-corrosion is established. From electrochemical tests, solutions analysis (AAS, ICP ...) and local pH measurements are performed to quantify species passing into solution. These results are input data to define a representative environment.New electrochemical tests are then performed in this representative solution to study the impact of this medium on the steel cords corrosion.

Ce travail de thèse est une contribution à la valorisation des écorces de l’orange « Maltaise demi-sanguine » tunisienne. L’objectif de ce travail est (i) d’étudier l’efficacité des différentes méthodes d’extraction en termes de teneurs en phénols totaux (PT), en flavonoïdes totaux (FT), en flavonoïdes individuels (FI) et en activité antioxydante des extraits et (ii) d’examiner l’effet inhibiteur de l’extrait contre la corrosion de l’acier en milieu acide et basique. Pour cela, cinq méthodes d’extraction ont été utilisées : l’extraction conventionnelle par solvant, ECS (éthanol (80%), m/v: 5g:50ml, 30 min, 35°C et agitation mécanique à l'obscurité, 3 extractions successives), l’extraction assistée par micro-ondes, EAM (éthanol (80%), m/v: 5g:50ml, 3 extractions successives, 180s, 67-108°C et 100-400W ou à 35°C), l’extraction assistée par ultrasons, EAU (éthanol (80%), m/v: 5g:50ml, 30 min, 35°C, 100-200W et 3 extractions successives), l’extraction sous haute pression, EHP (éthanol (80%), m/v: 5g:50ml, 30 min, 35°C, 0,1-100 MPa et 1 seule extraction) et l’extraction par CO2 supercritique, SC-CO2 (éthanol (80%), m/v: 5g:50ml, 30 min, 35-80°C/10-22 MPa et 3 extractions successives). Ce coproduit est riche en ingrédients fonctionnels comme les phénols totaux (1,968±0,002 g EAG/100g MS) et la vitamine C (0,105±0,003 g/100g MS). Dix flavonoïdes individuels (FI) ont été identifiés dans l’extrait des écorces de l’orange Maltaise. La néohespéridine (0,860±0,003 g/100g de poudre des écorces d’orange) et l’hespéridine (0,551±0,001 g/100g de poudre des écorces d’orange) sont les composés majoritaires. Les conditions opératoires d’extraction qui ont permis d’obtenir les teneurs les plus élevées en PT et FT sont 200 W, 76°C pendant 180s pour l’EAM, 125 W pendant 30 min à 35°C pour l’EAU, 80°C et 10 MPa pour l’extraction SC-CO2 et 50 MPa, 35°C pendant 30 min pour l'EHP. La comparaison des différentes méthodes d’extraction aux mêmes conditions opératoires (m/v:5g/50ml, éthanol 80%, 35°C, 3 extractions successives) montre que l’EAM présente les teneurs les plus élevées en PT et en FT, suivie par EAU, ECS, EHP et l’extraction SC-CO2, ainsi qu’en flavonoïdes individuels majoritaires. Cependant, la valeur de l’activité antioxydante n’est pas systématiquement corrélée à la teneur en phénols la plus élevée et elle diffère selon le test utilisé. Pour le test ABTS, l’activité antioxydante suit l’ordre décroissant suivant : EHP, ECS, SC-CO2, EAM, EAU, alors que c’est EHP, ECS, EAM, EAU, SC-CO2, pour le test DPPH. L’étude de l’effet anti-corrosion de l’extrait des écorces de l’orange Maltaise ainsi que ses composés antioxydants majoritaires (la néohespéridine, la naringine et l’acide ascorbique) a révélé une efficacité d’inhibition significative de la corrosion de l’acier par l’extrait des écorces d’orange (95%) par rapport à celle de ses composés antioxydants individuels : l’acide ascorbique (92%), la néohespéridine (87%) et la naringine (56%). Le potentiel anti-corrosion de l'extrait des écorces d'orange n’est pas due uniquement à l'activité antioxydante de ces composés mais probablement à des actions en synergie de différentes molécules et à la formation d'un film tridimensionnel de surface attribué à d’autres composés présents dans l’extrait comme la pectine / This work is a contribution to the valorization of “Maltease peel”. The objectives of this research are (i) to study the efficiency of different extraction methods in terms of total phenol contents (TPC), total flavonoid contents (TFC), individual flavonoids (FI) and antioxidant activity of extracts and (ii) to examine the corrosion inhibition of carbon steel in acidic and basic medium by orange peel extract and its main antioxidant compounds. For this, five extraction methods were used: conventional solvent extraction, CSE (ethanol (80%), m/v: 5g:50ml, 30 min, 35°C, mechanical stirring in the dark and 3 successive extractions), microwave assisted extraction, MAE (ethanol (80%), m/v: 5g:50ml, 3 successive extractions, and 180s, 67-108°C, 100-400W or at 35°C), ultrasound-assisted extraction, UAE (ethanol (80%), m/v: 5g:50ml, 30 min, 35°C, 100-200W and 3 successive extraction), high-pressure extraction, HPE (ethanol (80%), m/v: 5g:50ml, 30 min, 35°C, 0,1-100 MPa and one extraction) and supercritical CO2 extraction, SC-CO2 (ethanol (80%), m/v: 5g:50ml, 30 min, 35-80°C/10-22 MPa and 3 successive extractions). This byproduct is rich in functional ingredients such as total phenols (1.96 ±0.002 g GAE/100g DM) and vitamin C (0.10±0.003 g/100g DM). Ten individual flavonoids (FI) were identified in the extract of Maltease orange peel. Neohesperidin (0.860±0.003 g/100g orange peel powder) and hesperidin (0.551±0.001 g/100g orange peel powder) are the major compounds. The operating conditions of extraction that have achieved the highest levels of total phenol and flavonoid contents are 200 W, 76°C during 180s for MAE; 125 W during 30 min at 35°C for UAE; 80°C and 10 MPa for SC-CO2 extraction and 50 MPa,35°C during 30 min for HPE. The comparison of the different extraction methods performed at the same operating conditions (m/v: 5g/50ml, 80% ethanol, 35°C, 3 successive extractions) shows that the MAE has the highest levels of TPC and TFC, followed by UAE, CSE, HPE and SC-CO2 extraction, as well as the major individual flavonoids. However, results concerning antioxidant activity cannot be correlated to TPC, TFC or individual flavonoids and it differs depending on the test used. Orange peel extracted by HPE presents higher radical scavenging capacity compared to extracts obtained by other extraction methods. Moreover, it can be noticed a significant decrease of the antioxidant activity measured by the ABTS method in the following order: HPE, CSE, SC-CO2, MAE, UAE, whereas, it is EHP, ECS, EAM, EAU, SC-CO2 extraction for DPPH test. The study of the anti-corrosion effect of the orange extract and its antioxidant compounds (neohesperidin, naringin and ascorbic acid) showed a significant inhibition effectiveness of the corrosion steel with orange peel extract (95%) relative to that of its antioxidant compounds: ascorbic acid (92%), neohesperidin (87%) and naringin (56%). The anti-corrosion efficiency of orange peel extract is not only due to the antioxidant activity of identified compounds, but probably also to a synergic effect of molecules and to the formation of a three-dimensional surface of the film. This film can be formed due to the presence of other compounds in the extract such as pectin

Das unerwünschte Aufwachsen oder Anhaften von Eis an z.B. Windenergieanlagen und Wärmetauschern kann zum Funktionsverlust oder zur temporären Stilllegung der gesamten technischen Anlage führen. Bekannte Abwehrmechanismen sind das aktive Beheizen der Oberflächen oder der Einsatz von Enteisungschemikalien. Um den Verbrauch der hierfür benötigten elektrischen Energie oder Enteisungsmittel zu minimieren, werden in zunehmendem Maß passive Oberflächenbeschichtungen zur Gefrierverzögerung und Adhäsionsminimierung entwickelt. Der Einsatz pyroelektrischer Materialien bietet einen Lösungsansatz, der über bisher bekannte Abwehrstrategien hinausgeht. Es wird angenommen, dass pyroelektrisch generierte Oberflächenladungen während der Abkühlung entweder förderlich oder verzögernd auf die Eiskeimbildung wirken können. Dünne Schichten aus pyroelektrischem Poly-(Vinylidenfluorid - co - Trifluorethylen) haben wegen ihrer leichten Verarbeitbarkeit, hohen Flexibilität und pyroelektrischen Eigenschaften Interesse an ihrer Anwendung als funktionelle Beschichtung geweckt. Für eine industrielle Anwendung von P(VDF-TrFE) ist jedoch ein vertieftes Verständnis darüber erforderlich, wie sich der Beschichtungsprozess auf die resultierende Kristallinität, kristallographische Orientierung und Rauheit auswirkt. Die Morphologie teilkristalliner P(VDF-TrFE)-Beschichtungen wurde in dieser Arbeit in Abhängigkeit der Beschichtungsmethode, des Lösungsmittels, der Schichtdicke und der Wärmebehandlung mithilfe von Röntgenweitwinkelstreuung, Röntgenreflektometrie und Infrarot-Reflexions-Absorptions-Spektroskopie untersucht. Mit Hilfe von Rasterkraftmikroskopie- und Kontaktwinkel-Messungen wurden die resultierende Topographie und Rauheit der Schichten überprüft. Auf Grundlage der Ergebnisse dieser Messungen kann die dominierende edge-on Orientierung der P(VDF-TrFE)-Polymerketten entweder mit einem transkristallin-artigen Mechanismus oder Konfinement-Effekten erklärt werden. An den P(VDF-TrFE)-Dünnschichten wurde eine Vielzahl von Vereisungsexperimenten mit aufliegenden Wassertropfen durchgeführt, um den Einfluss der verschiedenen Schichtparameter wie Polarisierungsrichtung, Schichtdicke, verwendetes Lösungsmittel, Beschichtungstechnologie, Substrat und Wärmebehandlung auf die erreichbare Gefrierverzögerung unabhängig voneinander zu ermitteln. Die Rauheit der Schichten sowie substratspezifische Entnetzungserscheinungen veränderten hierbei signifikant die Verteilung der Gefriertemperaturen von Wassertropfen in Kontakt mit den P(VDF-TrFE)-Dünnschichten. Im Gegensatz dazu wurde kein signifikanter Einfluss der Dicke, Morphologie oder des pyroelektrischen Effekts auf die erreichbare Gefrierverzögerung gefunden. Es kann demnach geschlussfolgert werden, dass die heterogene Eiskeimbildung stärker durch lokale Rauheiten im nm-Bereich beeinflusst wird als durch integrale Eigenschaften wie beispielsweise Oberflächenladungen. Die Eisadhäsion auf P(VDF-TrFE) wird hauptsächlich durch Rauheiten im µm-Bereich, die Umgebungstemperatur und den Ionengehalt der flüssigen Phase bestimmt. Auch hier konnte kein signifikanter Einfluss geladener Oberflächen auf die Haftfestigkeit von Eis ausfindig gemacht werden. Statistische Tests ergaben, dass die Verteilung der Gefriertemperaturen unabhängiger Tropfen auf Oberflächen einem Spezialfall der Extremwertstatistik, der so genannten Gumbel-Verteilung, entspricht. Dies ermöglicht die Definition neuartiger Temperaturkennwerte für die Weiterentwicklung und Prüfung von Anti-Eis-Oberflächen.:Inhaltsverzeichnis 1. Einleitung und Motivation 2. Stand der Forschung 2.1. Pyroelektrika 2.1.1. Der pyroelektrische Effekt 2.1.2. Pyroelektrische Werkstoffe 2.1.3. Stabilität pyroelektrischer Materialien in wässrigen Medien 2.1.4. PVDF und P(VDF-TrFE) 2.2. Elektrochemische Doppelschicht 2.2.1. Aufbau und Modelle 2.2.2. Ursachen für Ladungen an Grenzflächen 2.2.3. Isoelektrischer Punkt und Ladungsnullpunkt 2.2.4. Orientierung von Wassermolekülen in der EDL 2.3. Vereisung 2.3.1. Wasser und Eis 2.3.2. Anti-Eis Strategien 2.3.3. Gefrierverzögerung 2.3.4. Eisadhäsion 2.4. Pyroelektrika in wässrigen Medien 2.4.1. Charakterisierungsmöglichkeiten 2.4.2. Anwendungsfelder 3. Materialien und Methoden 3.1. Materialien 3.2. Herstellung pyroelektrischer Beschichtungen 3.3. Schichtcharakterisierung 3.4. Vereisungsneigung 3.5. Statistische Methoden 4. Ergebnisse 4.1. Charakterisierung der P(VDF-TrFE) Beschichtungen 4.1.1. Schichtdicke (Ellipsometrie) und mechanische Eigenschaften 4.1.2. Morphologie (DSC, GIWAXS, XRR, IRRAS) 4.1.3. Elektrische Eigenschaften 4.1.4. Topographie (AFM und Kontaktwinkel) 4.2. Vereisungsneigung von P(VDF-TrFE) 4.2.1. Gefrierverzögerung 4.2.2. Eisadhäsion 4.3. Vergleichsmessungen auf poliertem Aluminium 4.3.1. Kontaktwinkel 4.3.2. Gefrierverzögerung 4.3.3. Eisadhäsion 5. Diskussion 5.1. Schichtherstellung, -charakterisierung und -eignung 5.1.1. Schichtdicke 5.1.2. Eignung der Charakterisierungsmethoden 5.1.3. Vergleich von Dip- und Spin-Coating 5.1.4. Eignung von P(VDF-TrFE) für Anti-Eis-Beschichtungen 5.2. Anti-Eis-Eigenschaften 5.2.1. Erreichbare Gefrierverzögerung 5.2.2. Eisadhäsion 6. Zusammenfassung und Ausblick Literaturverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Symbol- und Abkürzungsverzeichnis Veröffentlichungen Anhang / Active de-icing of technical surfaces, such as for wind turbines and heat exchangers, currently requires the usage of heat or chemicals. Passive coating strategies that either postpone the freezing of covering water droplets or lower the ice adhesion strength would be beneficial in order to save costs and energy. One hypothesis is that pyroelectric active materials can either delay or promote heterogeneous ice nucleation because of the surface charges generated when these materials are subject to a temperature change. Pyroelectric poly-(vinylidene fluoride - co - trifluoroethylene) P(VDF-TrFE) thin films have created interest in their application because of their easy processibility, high flexibility and ferroelectric properties. The industrial application of P(VDF-TrFE) requires an understanding of the deposition process of films and in particular the resulting crystallinity, crystallographic orientation and roughness. In this work it has been proposed that an interface-mediated crystallization process occurs when P(VDF-TrFE) thin films are deposited from a solvent, resulting in a dominantly edge-on orientation caused either by a transcrystallinity mechanism or confinement effect. The morphology of the semi-crystalline thin film was studied as a function of the deposition method, solvent, film thickness and annealing temperature by grazing incidence wide-angle X-ray scattering, X-ray reflectometry and infrared reflection absorption spectroscopy. Atomic force microscopy measurements were used to examine the resulting topography and contact angle measurements to additionally verify the low roughness of the coatings. Freezing experiments with water droplets subjected to a cooling rate of 1K/min were made on P(VDF-TrFE) coatings in order to separate the effect of the different film parameters such as the poling direction, film thickness, used solvent, deposition process, underlying substrate and annealing temperature on the achievable supercooling. The topography and substrate-specific dewetting effects significantly changed the distribution of freezing temperatures of water droplets in contact with the P(VDF-TrFE) thin films. In contrast, no significant effect of the thickness, morphology or pyroelectric effect of the as-prepared domain-state on the freezing temperatures was found. Statistical tests revealed that the distribution of freezing temperatures of individual droplets deposited on surfaces match a special case of extreme-value statistics, the so-called Gumbel-distribution. This allows for the definition of novel parameters for the development and testing of anti-icing surfaces. The adhesion strength of ice to P(VDF-TrFE) is mainly determined by the topography, temperature and ion-content of the liquid phase. In contrast, surface charges do not significantly influence the ice adhesion strength.:Inhaltsverzeichnis 1. Einleitung und Motivation 2. Stand der Forschung 2.1. Pyroelektrika 2.1.1. Der pyroelektrische Effekt 2.1.2. Pyroelektrische Werkstoffe 2.1.3. Stabilität pyroelektrischer Materialien in wässrigen Medien 2.1.4. PVDF und P(VDF-TrFE) 2.2. Elektrochemische Doppelschicht 2.2.1. Aufbau und Modelle 2.2.2. Ursachen für Ladungen an Grenzflächen 2.2.3. Isoelektrischer Punkt und Ladungsnullpunkt 2.2.4. Orientierung von Wassermolekülen in der EDL 2.3. Vereisung 2.3.1. Wasser und Eis 2.3.2. Anti-Eis Strategien 2.3.3. Gefrierverzögerung 2.3.4. Eisadhäsion 2.4. Pyroelektrika in wässrigen Medien 2.4.1. Charakterisierungsmöglichkeiten 2.4.2. Anwendungsfelder 3. Materialien und Methoden 3.1. Materialien 3.2. Herstellung pyroelektrischer Beschichtungen 3.3. Schichtcharakterisierung 3.4. Vereisungsneigung 3.5. Statistische Methoden 4. Ergebnisse 4.1. Charakterisierung der P(VDF-TrFE) Beschichtungen 4.1.1. Schichtdicke (Ellipsometrie) und mechanische Eigenschaften 4.1.2. Morphologie (DSC, GIWAXS, XRR, IRRAS) 4.1.3. Elektrische Eigenschaften 4.1.4. Topographie (AFM und Kontaktwinkel) 4.2. Vereisungsneigung von P(VDF-TrFE) 4.2.1. Gefrierverzögerung 4.2.2. Eisadhäsion 4.3. Vergleichsmessungen auf poliertem Aluminium 4.3.1. Kontaktwinkel 4.3.2. Gefrierverzögerung 4.3.3. Eisadhäsion 5. Diskussion 5.1. Schichtherstellung, -charakterisierung und -eignung 5.1.1. Schichtdicke 5.1.2. Eignung der Charakterisierungsmethoden 5.1.3. Vergleich von Dip- und Spin-Coating 5.1.4. Eignung von P(VDF-TrFE) für Anti-Eis-Beschichtungen 5.2. Anti-Eis-Eigenschaften 5.2.1. Erreichbare Gefrierverzögerung 5.2.2. Eisadhäsion 6. Zusammenfassung und Ausblick Literaturverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Symbol- und Abkürzungsverzeichnis Veröffentlichungen Anhang

This diploma thesis deals with the issue of lithium-ion accumulators. The thesis focuses on the negative electrode of lithium-ion accumulators made of natural graphite. The first part of this thesis points to the issue of electrochemical cells. In the theoretical part the thesis deals with the SEI layer, advantages, disadvantages, characteristics, operating principle and the use of lithium-ion accumulators. The practical part focuses on the electrochemical properties of negative electrode, especially the determination of the diffusion coefficient. Thesis also deals with electrochemical impedance spectroscopy (EIS) and its use in determining the equivalent replacement circuit and calculating the diffusion coefficient.

This thesis deals with the characterization of electrochemical corrosion properties of magnesium alloys as promising materials for biomedical applications. The wrought alloys AZ31 and AZ61 were used and exposed to corrosive environments of Hanks solutions (SBF) to simulate environmental conditions in living organisms. For the evaluation of the surfaces was used scanning electron microscopy (SEM) with elemental analysis measured by energy-dispersive spectroscopy (EDS). Short-term (5 min) and long-term (72 h) corrosion tests were conducted in order to optimize the measurement methodology and obtain corrosion parameters - especially corrosion potential (Ekor), corrosion current density (ikor) and polarisation resistance (RP). To evaluation of the short-term tests were by potentiodynamic tests, namely the linear polarization (LP) test. Long-term tests were measured by electrochemical impedance spectroscopy (EIS). Effects of the composition of the alloys (AZ31 and AZ61), surface treatment (grinding and polishing) and the composition of the solution (SBF without Ca, Mg, and with Ca, Mg) were compared. Complex corrosion behaviour in time was characterized and corrosion mechanisms were discussed.

This thesis deals with organic materials and determining their electrical parameters. In the thesis are discussed methods of deposition of organic layers and their measurement. Described are the aspects, which are characteristic for organic materials. They will briefly mention some new components and commercial systems. Special attention is given to conducting polymers and determining their parameters. In the experimental part were measured VA and impedance characteristics of the conductive polymer PEDOT-PSS. The research was also about material degradation in time and effects of thickness on the electrical parameters.