There is a paramount need for online university education to effectively contribute in the development of students' ability to construct and create new knowledge. Online learning should thus go beyond the production of knowledge for knowledge's sake, but should result in relevant and meaningful learning on the part of the online learner. In addition, online learning ought to result in the application of knowledge to practice. While gains made by constructivism and observational learning are well documented, research addressing online media blends that best encourage constructivist and observational learning in open and distance and e-learning (ODeL) contexts is limited. In addition, guidelines that can be used by online learning facilitators and policy makers regarding media for constructivist and observational learning were lacking when this research was conducted. The research was deemed significant in contributing to the development of an online learning framework that could be used to guide policy formulation and practice in the area of online course implementation in ODeL institutions. Using an explorative qualitative approach, this study explored online media blends for constructivist and observational learning. The study comprised three phases. The first phase was a meta-ethnography study whose objective was to synthesise previous research theses in order to gain an understanding of lecturers' and students' experiences of online media, constructivism and observational learning. The second phase consisted of a phenomenological study conducted at the University of South Africa, to explore lecturers' experiences of online media in the facilitation of constructivism and observational learning. The final phase of the research was the development of a framework based on constructivism and observational learning to guide online teaching and learning. The findings of this research study revealed that lecturers did not use media blends to a large extent in their interaction with students. The study indicated that some cognitive processes need to be exercised on the part of the facilitators when online learning is offered. It is concluded that during the curriculum planning phase, lecturers should decide on methods and media to arouse the students' attention during online courses. This also implies a more reasonable lecturer­ student ratio because large numbers of students per lecturer is not feasible in online learning. / Curriculum and Instructional Studies / D. Ed. (Curriculum Studies)

Les objectifs de cette thèse consistent à identifier les morphologies adoptées par des mélanges d’élastomères chargés en noir de carbone, à étudier l’influence de l’introduction de charges sur ces morphologies mais aussi de détecter la localisation de la charge dans ces mélanges. Dans une dernière partie, l’impact de ces différentes structures sur les défauts d’extrusion est abordé. Ces travaux concernent l’étude des coupages caoutchouc naturel / styrene-butadiene rubber (NR / SBR) et polybutadiène / styrene-butadiene rubber (BR / SBR) non vulcanisés. Dans un premier temps, les morphologies adoptées par ces mélanges non chargés ont été identifiées grâce à plusieurs protocoles expérimentaux. L’influence de l’introduction de noir de carbone ainsi que l’étude de la localisation de la charge dans ces mélanges ont constitué une seconde étape dans ces travaux. Aucune localisation préférentielle de la charge n’a été détectée pour ces mélanges. Un système ségrégé a donc été réalisé par la suite. Enfin, le comportement en extrusion de ces mélanges a été simulé par rhéométrie capillaire et des observations de défauts d’aspect ont été faites. La ségrégation du noir de carbone ne semble pas entraîner la création de défauts d’aspect, sauf dans le cas d’une localisation dans la matrice / The purpose of this project is to investigate the morphology of elastomeric blends filled with carbon black, the localization of the filler in these blends and the structure impact on their processing. This work concerns uncured natural rubber / styrene-butadiene rubber (NR / SBR) blends and butadiene rubber / styrene-butadiene rubber (BR / SBR) blends. Firstly, the morphology of these blends unfilled was described by different experimental procedures over the entire composition range. Secondly, the impact of the filler on the morphology and the localization of it on the blends were studied. No preferential localization was observed in our case. Another blend with a segregation was realized. And finally, the processing of these elastomeric blends was simulated by capillary rheology to detect the formation of flow instabilities. Few melt fractures were observed, except when the filler is localized in the matrix

Recycled material produced during three months from packing polyethylene foils coming from three suppliers was analysed together with one recycled material under complaint from the point of melt flow index (MFI), composition and mechanical properties. The addition of linear low density polyethylene (LLDPE) into the recycled material was studied as well. It was measured melt flow index (MFI), Differential scanning calorimetry (DSC) together with Thermogravimetry methods were used to determine composition. Selected materials were pressed to obtain films with the thickness of 1 mm to determine tensile properties. Recycled materials contained 40–65% LLDPE, small amount of polypropylene as well as chalk. The content of LDPE and LLDPE varied within one supplier and thus mechanical properties did. The results showed the difference in quality of PE films separation among all suppliers. The problems with workability of material under complaint were caused by the material composition – the amount of LLDPE predominated. The addition of LLDPE into the recycled material in the range of 5–20 % increased MFI by 13-78%. Mechanical properties of blends rich in LLDPE were similar to those of clear LLDPE. The presence of LDPE influenced more markedly only the strength to break. The blends of LDPE and LLDPE were evaluated as immiscible but with high affinity of the components with increasing contend of LLDPE. No material was chemically degraded. The methods commonly performed in manufacture, especially MFI, are not able to differentiate LDPE form LLDPE – recommended is DSC.

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No description available.

Les recherches réalisées au cours de ce doctorat portent sur l’étude et l’optimisation de mélanges de polymères, utilisés en tant qu’électrolytes solides polymères (SPEs) dans les batteries lithium et lithium-ion. Les composants de la batterie doivent pouvoir être mis en forme par un procédé sans solvant (extrusion), afin de réduire les impacts du solvant sur les propriétés de la batterie et d’optimiser la production (diminution de la toxicité et du temps de production). Pour répondre à ces objectifs, une étude a d’abord été menée sur des mélanges de polymères, sélectionnés d’après leurs propriétés individuelles, en se concentrant notamment sur les interactions entre le sel de lithium et chaque polymère. Un classement des interactions a été développé et a permis de montrer que le principal facteur les favorisant est le nombre donneur des groupements fonctionnels polaires présents sur les chaînes polymères. Enfin, les effets de ces interactions sur les phénomènes de transport ionique dans les mélanges ont été investigués. Par la suite, l’étude s’est focalisée sur les couples de polymères ayant des propriétés prometteuses et complémentaires, tels que le poly(oxyde d’éthylène) (POE) ou le polycaprolactone (PCL), qui ont des conductivités ioniques élevées, et un copolymère butadiène-acrylonitrile hydrogéné (HNBR), qui possède des propriétés mécaniques intéressantes mais une conductivité ionique limitée. Il a été conclu que ces mélanges présentent des propriétés encourageantes, comparées aux SPEs composés d’un unique polymère, telles que des conductivités ioniques élevées sur une large plage de températures, ainsi que de meilleures propriétés de stabilités mécanique et thermique. La dernière partie de ces travaux s’est portée sur l’optimisation des propriétés de ces mélanges, par une méthode innovante de réticulation sélective d’une des phases. Pour conclure ce doctorat, l’objectif final a été de réaliser un prototype performant de batterie lithium tout solide, entièrement obtenu par extrusion, et dont l’électrolyte et le liant au sein des électrodes composites sont composés des électrolytes polymères optimisés. Les résultats prometteurs obtenus ont permis la soumission d’un brevet, en association avec le partenaire industriel (TotalEnergies). / The research carried out during this PhD is focused on the study and optimization of polymer blends, used as solid polymer electrolytes (SPEs) in lithium and lithium-ion batteries. All components of the battery must be shaped by a solvent-free process (extrusion), in order to limit impacts of the solvent on the battery properties and improve the production process (reduce toxicity and production time). To achieve these objectives, a study was first conducted on a set of polymer blends, selected on the basis of their individual properties, with particular emphasis on the interactions between the lithium salt and each polymer. A ranking of the lithium salt solvating ability of these polymers was developed and revealed that the main factor affecting these interactions is the donor number of polar functional groups on the polymer backbones. The effects of these interactions on the ionic transport phenomena in blend electrolytes have been examined. Subsequent work focused on polymer couples with the most promising and complementary properties, such as poly(ethylene oxide) (PEO) or polycaprolactone (PCL), which exhibit high ionic conductivities, and a hydrogenated nitrile butadiene rubber (HNBR) with interesting mechanical properties but a lower ionic conductivity. It was concluded that these blends show encouraging properties, compared to single-polymer SPEs, such as higher ionic conductivities over a wide temperature range, as well as improved mechanical and thermal stability properties. The final research project was the optimization of these blend electrolytes using an innovative method of selective cross-linking of one of the polymer phases. The main aim of this thesis was to develop an efficient prototype of an all-solid-state lithium battery, entirely obtained by extrusion, in which both the electrolyte and the binder of the composite electrodes are composed of optimized polymer electrolytes. The promising results obtained have led to the filing of a patent, in association with the industrial partner (TotalEnergies).

Refrigeration plays a vital role today in various residential, commercial, and industrial processes, requiring refrigerants to facilitate the cooling or heating processes. Over time, refrigerants have undergone significant changes to meet technological, social, environmental, and economic needs. Refrigerants' evolution can be categorized into four generations. The first three generations come from the early use of natural compounds (CO2, SO2), to the dominance of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), followed by the ozone protection era of hydrofluorocarbons (HFCs)1. However, HFCs presented new challenges due to their high Global Warming Potential (GWP), leading to the development of 4th generation refrigerants formed by hydrofluoroolefins (HFOs) like R- 1234yf. However, to minimize GHG emissions even more and phase out of high Global Warming Potential (GWP) alternatives, following the Montreal Protocol (globally) and the F-Gas Regulation (Europe), low-GWP refrigerants emerge. This group includes compounds with a GWP value below or equal to 150, such as natural refrigerants, new synthetic (R-1234yf) or older compounds (R-152a). The research gap in this MSc thesis addresses the management of particularly synthetic low-GWP refrigerants throughout their entire useful lifecycle, focusing on the tank-to-grave concept. This concept addresses the useful life of the refrigerants, starting with their procurement and charging into refrigeration and heat pump units (during manufacturing), and then their distribution, use, and end-of-life management. This, therefore, excludes the extraction of raw materials and manufacturing of refrigerants. However, the Life Cycle Assessment (LCA) approach analyses environmental impacts in all product phases (including raw materials extraction). Within this context, this thesis explores the different stakeholder procedures and activities for managing refrigerants throughout their lifetime. Different stakeholders or organizations, including heat pump/refrigeration system manufacturers, their service organizations, end-users, and end- of-life management organizations are involved in this process. Whenever possible, a representative or more from a given stakeholder category was thus interviewed. However, possible limitations such as lack of certain stakeholder involvement, limited information about some stakeholder groups, as well as the assumption of generalisability of the results obtained, are considered throughout this report. For stakeholder categories for which interviewing was not possible, literature-based mapping was conducted. Furthermore, comprehending the current legislation and standards was done as it is essential to grasp the complete process of handling of refrigerants. Additionally, as it concerns the management of refrigerants throughout their useful lifecycle, studying their potential applicability with Life Cycle Assessment (LCA) is of interest. Finally, the entire project is analysed from a sustainability perspective, exploring the advantages and disadvantages it entails. Before delving into the information about stakeholders, it is essential to establish a theoretical context related to the process of refrigerant management. The first key role is to understand Life Cycle Thinking (LCT), LCA and Material Flow Analysis (MFA) and how to apply these to the management of refrigerants. In addition, the concept of tank-to-grave management is explained, along with the various groups or organizations involved in different phases of a refrigerant's life. These groups include manufacturers, service organizations, supplier organizations, cold chain organizations, recovery organizations, reclamation organizations, disposal organizations as well as certain related associations and certifying bodies. Furthermore, given the importance of the concept of recovery in this project, its meaning is compared from the perspective of refrigerant management and waste hierarchy. Furthermore, the F-Gas Regulation and some of its articles, related to leakage control and the frequency of leakage checks according to the type of equipment used, how the recovery process should be carried out or the strategies related to market positioning and control of the use of these F-gases are studied. In addition, the Air-Conditioning, Heating and Refrigeration Institute (AHRI) standards are investigated, as they are widely used in the refrigeration sector and explain some procedures related to activities such as composition analysis or procedures to be performed with recovery equipment. Lastly, the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation and the potential implications of implementing the per-and poly-fluoroalkyl substances (PFAS) ban proposal are explored due to their significant possible impact on the refrigeration industry in future years. This is because PFAS includes almost all synthetic refrigerants. To gather information about the current situation and practices in the refrigeration sector, the research adopts a qualitative approach, centred on in-depth interviews with different stakeholders. These interviews provide valuable firsthand insights into the practices, experiences, and perceptions of stakeholders regarding the management of synthetic low-GWP refrigerants. These interviews were based on a series of questionnaires, developed, and customized within the project, according to the types of organization. Moreover, with the interviewees' consent, these interviews were recorded, and transcriptions were created. These transcripts were systematically coded and analysed to identify recurring themes and patterns, as well as differences between the different stakeholders’ inputs. The next point to address was the concept of sustainability. The goal is to introduce this concept and explain its significance in society, particularly with the implementation of initiatives like the United Nations Sustainable Development Goals (SDGs). Therein, these concepts were applied to the topic and scope of this master’s thesis, i.e., on refrigerants management, discussing some advantages, and disadvantages regarding the use of refrigerants and some steps of their management. The thesis shows that the current refrigeration industry is not only dominated by synthetic low-GWP refrigerants, but also natural refrigerants are widely used. Additionally, different opinions and methodologies arose regarding a series of topics. Firstly, when discussing whether they checked for changes in refrigerant composition, it was not possible to obtain a general trend. Secondly, for leak detection systems, different methodologies were used depending on the needs of the organisation, but both manual and fixed systems were mentioned. Finally, regarding end-of-life management, all organizations agreed that the first step should be the recovery of the refrigerant. After that, there are two different options: reclamation (purifying an old refrigerant to obtain one with the characteristics of a virgin refrigerant), and disposal (usually by sending the refrigerants to incineration). F-Gas Regulation and AHRI are the most widely used regulations at present, while organizations expect the PFAS ban to become a real regulation in the future. As a result, most organizations are leaning towards a future dominated by natural refrigerants, which may necessitate new regulations, certain technical changes, and possibly new business models. To conclude, tank-to-grave management of synthetic low-GWP refrigerants offers opportunities for the refrigeration industry, as this concept helps to let you know all the stakeholders involved and the processes they employ, and together with the application of the LCT approach, it is easier to understand how different activities, e.g., recovery and reclamation, can be improved to reduce the environmental impact of these compounds. The study finally considered both natural and synthetic low-GWP refrigerants. Moreover, technical aspects such as analysis composition or leak detection systems, together with end-of-life management approaches and techniques (reclamation or disposal) differed between organizations, so no global trend regarding the Swedish situation could be given. Finally, two possible scenarios arise regarding the legislation: on the one hand, if the PFAS ban proposal is not approved, the industry would continue phasing out high-GWP refrigerants while prioritising reclamation and/or waste energy use from incineration of synthetic low-GWP refrigerants. On the other hand, if the ban is approved, natural refrigerants would become the main and almost only option, requiring adjustments and compliance with new regulations due to their flammability. About the future work to do in this thesis, new interviews with stakeholders that were not interviewed the first time. Moreover, a second round of interviews to address doubts that have appeared. Finally, to study how the rate of reclaimed refrigerants can be increased. / Kylteknik spelar en avgörande roll idag i olika bostads-, kommersiella och industriella processer, och kräver köldmedier för att underlätta kyl- eller värmepumpsteknik processarna. Över tiden har köldmedium genomgått betydande förändringar för att möta teknologiska, sociala, miljömässiga och ekonomiska behov. Köldmediernas utveckling kan kategoriseras i fyra generationer. De första tre generationerna kommer från den föregående användningen av naturliga komponenter (CO2, SO2), till dominansen av klorfluorkarboner (CFCs) och hydroklorfluorkarboner (HCFCs), följt av ozonskyddsperioden med hydrofluorkarboner (HFCs). Dock presenterade HFCs nya utmaningar på grund av deras höga Globala Uppvärmningspotential (GWP), vilket ledde till utvecklingen av fjärde generationens köldmedier, som bildas av hydrofluorolefiner (HFOs) som R-1234yf. För att dock minska växthusgasutsläppen ännu mer och fasa ut hög-GWP-alternativ enligt Montrealkonventionen (globalt) och F-gasförordningen (Europa), utvecklades låg-GWP-köldmedier. Denna grupp inkluderar komponenter med ett GWP-värde som är lägre än eller lika med 150, såsom naturliga köldmedier, nya syntetiska (R-1234yf) eller äldre komponenter (R-152a). Forskningsgapet i denna exjobb behandlar hanteringen av särskilt låg-GWP- köldmedier under hela deras användbara livscykel och fokuserar på tank-till-grav-konceptet. Detta koncept tar upp köldmediernas användbara livslängd, börjande med deras upphandling och påfyllning i kylteknik- och värmepumpsenheter (under tillverkning), och sedan deras distribution, användning och hantering vid livets slutskede. Detta exkluderar därför utvinning av råmaterial och tillverkning av köldmedier. Medan Livscykelbedömningsmetoden (LCA) analyserar miljöpåverkan i alla produktfaser. Inom denna kontext syftar denna avhandling till att utforska de olika intressenternas procedurer och aktiviteter för att hantera köldmedium under deras livstid. Olika intressenter eller organisationer, inklusive tillverkare av värmepumpar/kylsystem, deras serviceorganisationer, slutanvändare och organisationer för hantering av livets slutskede, är involverade i denna process. När det var möjligt, intervjuades en representant eller flera från en given intressentkategori. Eventuella begränsningar såsom brist på viss intressentmedverkan, begränsad information om vissa intressentgrupper, samt antagandet om generaliserbarhet av de erhållna resultaten, beaktas genom hela denna rapport. För intressentkategorier där intervjuer inte var möjliga, genomfördes kartläggning baserad på litteratur. Vidare genomfördes en förståelse av nuvarande lagstiftning och standarder, eftersom det är väsentligt att förstå hela processen för hantering av köldmedium. Dessutom, då det gäller hanteringen av köldmedier under deras användbara livscykel, är det intressant att studera deras potentiella användbarhet med Livscykelbedömningen (LCA). Slutligen analyseras hela projektet ur ett hållbarhetsperspektiv, där fördelar och nackdelar utforskas. Innan vi dyker in i informationen om intressenter är det väsentligt att etablera en teoretisk kontext relaterad till processen för hantering av köldmedium. Den första nyckelrollen är att förstå Livscykeltänkande (LCT), LCA och Materialflödesanalys (MFA) och hur dessa kan tillämpas på hanteringen av köldmedier. Dessutom förklaras konceptet med tank-till-grav-hantering, tillsammans med de olika grupperna eller organisationerna som är involverade i olika faser av ett köldmedium liv. Dessa grupper inkluderar tillverkare, serviceorganisationer, leverantörsorganisationer, kyltekniskedjeorganisationer, återvinnings- och reklamationsorganisationer, avfallshanteringsorganisationer (som handlar kassering) samt vissa relaterade komponenter och certifierande organ. Vidare, med tanke på vikten av återvinningskonceptet i detta projekt, jämförs dess betydelse ur perspektivet av köldmediumshantering och avfallshanteringshierarkin. Vidare studeras F-gasförordningen och några av dess artiklar, relaterade till läckagekontroll och frekvensen för läckagekontroller enligt typen av utrustning som används, hur återvinningsprocessen bör genomföras eller strategier relaterade till marknadspositionering och kontroll av användningen av dessa F-gaser. Dessutom undersöks standarderna från Air-Conditioning, Heating and Refrigeration Institute (AHRI), eftersom de används brett inom kylteknisksektorn och förklarar vissa procedurer relaterade till aktiviteter såsom sammansättningsanalys eller procedurer som ska utföras med återvinningsutrustning. Slutligen utforskas REACH-förordningen (Registration, Evaluation, Authorisation and Restriction of Chemicals) och de potentiella konsekvenserna av att genomföra förslaget om förbud mot per- och polyfluoralkylämnen (PFAS), på grund av deras betydande möjliga påverkan på kyltekniskaindustrin under kommande år. Detta beror på att PFAS inkluderar komponenter som ingår i gruppen med låg-GWP- köldmedier. För att samla information om den nuvarande situationen och praxis inom kylteknisksektorn använder forskningen en kvalitativ metodik, fokuserad på djupgående intervjuer med olika intressenter. Dessa intervjuer ger värdefulla förstahandsinsikter i intressenternas praxis, erfarenheter och uppfattningar om hanteringen av låg-GWP- köldmedier. Dessa intervjuer baserades på en serie enkäter som utvecklades och anpassades inom projektet, enligt organisationstyper. Dessutom spelades dessa intervjuer in med intervjuobjektens samtycke, och transkriptioner skapades. Dessa avskrifter kodades och analyserades systematiskt för att identifiera återkommande teman och mönster samt skillnader mellan olika intressenters synpunkter. Det nästa punkten att behandla var begreppet hållbarhet. Målet är att introducera detta begrepp och förklara dess betydelse i samhället, särskilt med införandet av initiativ som FNs hållbarhetsmål (SDGs). Därigenom tillämpades dessa begrepp på ämnet och omfattningen av denna exjobb, det vill säga hantering av köldmedier, och diskuterades vissa fördelar och nackdelar med användningen av köldmedium samt vissa steg i deras hantering. Uppsatsen visar att den nuvarande kyltekniskaindustrin inte bara domineras av låg-GWP-köldmedier, utan naturliga köldmedier används också i stor utsträckning. Dessutom framkom olika åsikter och metoder om en rad ämnen. För det första, när det diskuterades om de kontrollerade förändringar i köldmedier sammansättning, var det inte möjligt att få fram en allmän trend. För det andra, när det gäller läckagedetekteringssystem, användes olika metoder beroende på organisationens behov, men både manuella och fasta system nämndes. Slutligen, gällande hantering av livets slutskede, var alla organisationer överens om att första steget borde vara att återvinna köldmedier. Därefter finns det två olika alternativ: återvinning (rensa ett använt köldmedium för att erhålla ett med egenskaperna hos ett jungfruligt köldmedium) och kassering (vanligtvis genom att skicka köldmedier till förbränning). F-Gasförordningen och AHRI är de mest använda reglerna för närvarande, medan organisationer förväntar sig att förbudet mot PFAS kommer att bli en verklig reglering i framtiden. Som ett resultat lutar de flesta organisationer mot en framtid dominerad av naturliga köldmedier, vilket kan kräva nya regler, vissa tekniska förändringar och möjligen nya affärsmodeller. Sammanfattningsvis erbjuder tank-till-grav-hantering av låg-GWP-köldmedier möjligheter för kyltekniskaindustrin, då detta koncept hjälper till att identifiera alla involverade intressenter och de processer de använder sig av. Tillsammans med tillämpningen av LCT blir det lättare att förstå hur olika aktiviteter, t.ex. återvinning och rening, kan förbättras för att minska miljöpåverkan från dessa materialer. Studien beaktade både naturliga och låg-GWP- köldmedier. Dessutom skilde sig tekniska aspekter såsom sammansättningsanalys eller läckagedetekteringssystem, tillsammans med slutskedeshanteringsmetoder och tekniker (återvinning eller kassering) mellan organisationer, så ingen global trend angående den svenska situationen kunde fastställas. Slutligen framträder två möjliga scenarier avseende lagstiftningen: å ena sidan, om förslaget om förbud mot PFAS inte godkänns, skulle industrin fortsätta fasa ut hög-GWP- köldmedier och samtidigt prioritera rening och/eller energiåtervinning från förbränning av låg-GWP- köldmedier. Å andra sidan, om förbudet godkänns, skulle naturliga köldmedier bli huvudalternativet och nästan det enda alternativet, vilket kräver anpassningar och efterlevnad av nya regler på grund av deras brandfarlighet. Om framtida arbete i denna avhandling, inkluderar det nya intervjuer med intressenter som inte intervjuades första gången. Dessutom en andra omgång intervjuer för att ta upp de tvivel som har uppstått. Slutligen, att studera hur återvunna köldmedium kan öka i takt.

Les polymères conjugués semi-conducteurs sont des matériaux prometteurs pour des applications en optoélectronique et pour la fabrication de dispositifs de conversion d'énergie flexibles. Ils sont toutefois difficilement mis en forme en raison de la rigidité de leur structure. Le poly(3-hexylthiophène) (P3HT) est souvent utilisé comme polymère conjugué organique modèle. Sa mise en forme et ses propriétés peuvent être optimisées en l'incorporant dans une matrice polymère et en favorisant l’orientation moléculaire de ses chaînes. Cette orientation peut être induite dans un matériau lors de sa mise en forme, notamment lors de la préparation de fibres par électrofilage. Le projet vise à préparer des matériaux optimisant l'orientation du P3HT et à développer des outils pour caractériser l'organisation moléculaire du P3HT dans ces matériaux. Plus spécifiquement, la première étude consiste à comprendre l'effet de la matrice polymère sur le comportement du P3HT dans des nanofibres électrofilées. Celles-ci sont préparées en mélangeant le P3HT à une matrice polymère amorphe de poly(méthacrylate de méthyle) (PMMA) atactique ou fortement cristalline de poly(oxyde d'éthylène) (POE), et l’orientation des chaînes de P3HT est mesurée par spectroscopie Raman. Les résultats montrent que la capacité du POE à cristalliser, contrairement au PMMA, contraint les chaînes du P3HT à s'orienter le long de l’axe de la fibre, ce qui devrait améliorer ses propriétés de transport de charge. La calorimétrie différentielle à balayage et la microscopie optique et électronique à balayage permettent respectivement d'analyser les propriétés thermiques et d'imager la morphologie des nanomatériaux. La seconde étude est de développer une approche pour identifier la transition vitreuse du P3HT dans des nanofibres électrofilées et des impressions 3D composées d’un mélange P3HT-POE. Nous suivons alors l'évolution de l’état d'agrégation du P3HT par spectroscopie de fluorescence et le déplacement de sa bande Raman associée au mode d’élongation C=C sur une gamme de températures afin d'observer sa transition de phase vitreuse à l'échelle du nanoobjet individuel. Une preuve de concept est réalisée par des analyses sur des films minces à base de P3HT pour ensuite analyser les échantillons d’intérêt. Les résultats de spectroscopie Raman et de fluorescence sur les nanomatériaux de P3HT sont comparés aux analyses DSC sur les matériaux macroscopiques. Le projet améliorera d'une part notre capacité à caractériser les nanomatériaux de P3HT et, d'autre part, à en optimiser les propriétés. De manière plus générale, nos résultats conduiront à terme à une meilleure compréhension des relations structure-mise en forme-propriété-fonction des polymères conjugués, contribuant à la préparation de nouveaux matériaux électroniques organiques plus performants. / Conjugated polymers are promising semiconducting materials for applications in flexible optoelectronic and energy conversion devices. However, they are difficult to process because of the rigidity of their polymer backbone. Poly(3-hexylthiophene) (P3HT) is often used as a model organic conjugated polymer. Its processing and its properties can be improved by incorporating it into a polymer matrix and by favoring the molecular orientation of its chains. This orientation can be induced in a material during its processing, notably during the preparation of fibers by electrospinning. The project aims to prepare materials optimizing the orientation of P3HT and to develop tools to characterize the molecular organization of P3HT in these materials. More specifically, the first study consists of understanding the effect of the polymer matrix on the behaviour of P3HT in electrospun nanofibers. These nanofibers are prepared by mixing P3HT with an amorphous atactic poly(methyl methacrylate) (PMMA) or highly crystalline poly(ethylene oxide) (PEO) polymer matrix, and the orientation of the P3HT chains is measured by Raman spectroscopy. The results show that the capability of POE to crystallize, unlike PMMA, constrains the chains of P3HT to orient themselves along the fiber axis, which could improve its charge transport properties. Differential scanning calorimetry and optical and scanning electron microscopy make it possible, respectively, to analyze the thermal properties and to image the morphology of the nanomaterials. The second study is to develop an approach to identify the glass transition temperature of P3HT in electrospun nanofibers and 3D prints composed of a P3HT-PEO blend. We then follow the evolution of the aggregation state of P3HT by fluorescence spectroscopy and the shift of the Raman band associated with the C=C elongation mode over a range of temperatures to observe its glass transition temperature at the scale of the individual nanoobject. A proof of concept is first realized by carrying out analyses on thin films based on P3HT, followed by the analysis of the samples of interest. Raman and fluorescence spectroscopy results on P3HT-containing nanomaterials are compared to DSC analyses on macroscopic materials. The project will improve our ability to characterize P3HT nanomaterials and to optimize their properties. More generally, our results will ultimately lead to a better understanding of the structure-processing-property-function relationships of conjugated polymers, contributing to the preparation of new, more efficient organic electronic materials.

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