Recently high temperature vulcanized (HTV) silicone rubber (SIR) / polymeric/composite insulators are gaining wider acceptance as overhead transmission line insulators for extra high voltage (EHV) and ultra-high voltage (UHV) systems due to some promising features like hydrophobicity recovery, light weight, ease of handling and installation, better pollution ashover performance, admirable resistance against vandalism etc. Since polymeric insula-tors are of recent origin, their long-term eld performance is yet to be understood. Owing to their organic nature, and exposure to environmental stresses like pollution, temperature, UV radiation, humidity, fog, rain etc., the insulator performance degrades over a period. The sheds/petticoats of the insulators become wettable leading to frequent ashover in humid and contaminated environment. Hence, long term reliability of the composite insulators is of foremost concern to the power utilities. The available literature on the long term eld performance of these insulators for di erent climatic conditions and under multiple environ-mental stresses for both the HTV SIR and Liquid Silicone Rubber (LSR) is scant. Also there is no reference standard for evaluation of these insulators for pollution/contamination test methods in the laboratory. However currently, CIGRE Work Group is working towards the standardization of the test methods for arti cial pollution tests for polymeric insulators. The thesis addresses some of the issues in detail. In the first part of the thesis, a new and simple pre-treatment methodology to achieve uniform contamination layer on inherently hydrophobic HTV SIR Insulator samples is presented for laboratory pollution performance evaluation. The surface water level di usion in the dipping period is found to make the insulator surface temporarily hydrophilic. Then the uniform contamination layer is applied by dipping the sample immediately in the pollution slurry. Exhaustive experiments were conducted on full scale SIR insulators as well as SIR slabs to investigate the hydrophilicity appearance on the SIR surface. A specially fabricated arrangement for assessment of Wettability Class (WC) is made as per IEC stds. The results of WC measurement and wet ashover studies support the temporary reduction in hydrophobicity of SIR due to dipping phase in the proposed pre-treatment methodology. The next part of the thesis presents the results for the effeect of long term thermal aging experimentation conducted on HTV SIR with difffeerent degrees of pollution (medium, heavy), the effeect of arid desert climate on polymeric insulators is studied. The experimental set-up consists of controlled HVAC source, temperature controlled furnace with a provision for high voltage (HV) and Leakage Current (LC) monitoring, a Digital Storage Oscilloscope (DSO), compact DAQ-9201 of National Instruments operated in LabVIEW platform etc. Two types of HTV SIR Insulators are considered for the study. Flat slabs as well as full-scale insulator samples of creepage length 725 mm are stressed simultaneously to simulate the in-service condition. The experimentation is conducted for about 575 hours with application of 21.0 kVrms at 60oC. The results of the hydrophobicity recovery for thermally aged contaminated polymeric insulators are reported. Besides, monitoring electrical and mechanical proper-ties, changes in material properties of SIR are also analyzed using Physiochemical analysis techniques like Fourier transform infrared (FTIR) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC). Some of the key findings of the study are increased surface oxidation, surface roughness and mechanical stress due to thermal aging of polymeric insulators. Experimental investigations show that the characteristics of power frequency component of leakage current can be linked with thermal aging of SIR. Further, a unique climatic aging experimental facility is established to evaluate the long-term reliability of SIR under environmental stresses like UV, Humidity, temperature and applied electric stress. The investigations are conducted on two different types of HTV SIR and LSR at samples as well as full-scale insulator samples. The experimentation is conducted for 500 hours with 10.0 kVrms at 50oC, with 85% humidity and 1 W/m2 UV ir-radiation which is in accordance with the aging cycle specified in IEC standard. The results of the comparative studies conducted for the electrical, mechanical and material properties indicate leakage current pulses, brittleness, Salt deposition for multistress aged samples. In summary, an attempt has been made to contribute a pollution methodology with sim-ple pre-treatment technique for inherently hydrophobic HTV SIR surface to achieve better uniformity of contamination layer. Also, electro-thermal and multiple stresses investigations were conducted for long term performance on polymeric insulators.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2016-11-17T17:43:21Z No. of bitstreams: 1 RODRIGUES_Karina_2015.pdf: 7918406 bytes, checksum: 5c7eded70cc8a9dd00ce5c1b2d70d846 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-11-17T17:43:31Z (GMT) No. of bitstreams: 1 RODRIGUES_Karina_2015.pdf: 7918406 bytes, checksum: 5c7eded70cc8a9dd00ce5c1b2d70d846 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-11-17T17:43:39Z (GMT) No. of bitstreams: 1 RODRIGUES_Karina_2015.pdf: 7918406 bytes, checksum: 5c7eded70cc8a9dd00ce5c1b2d70d846 (MD5) / Made available in DSpace on 2016-11-17T17:43:54Z (GMT). No. of bitstreams: 1 RODRIGUES_Karina_2015.pdf: 7918406 bytes, checksum: 5c7eded70cc8a9dd00ce5c1b2d70d846 (MD5) Previous issue date: 2015-06-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In this study, the wettability of porous anodic alumina (PAA) surfaces modified by plasma was investigated. The porous anodic alumina films were grown on aluminum substrate using a two step anodization procedure in oxalic acid solution under potentiostatic regime. The surfaces of PAA films were modified by plasma treatment or plasma deposition techniques. Prior to surface modification, the impurities were removed by a plasma cleaning procedure. Oxygen was used in plasma treatment in order to produce hydrophilic surfaces. On the other hand, the plasma deposition (in HMDSO or HMDSO + argon mixture) was performed to produce hydrophobic surfaces or less hydrophilic surface. Electropolished aluminum without PAA film were used as reference. The influence of substrate morphology on wettability was analyzed. The morphological characterization was performed by scanning electron microscopy (SEM). The microstructural analysis was carried out using Fourier Transformed Infrared Spectroscopy (FTIR). A goniometer was used to measure the contact angle and evaluate the wettability of electroplished aluminum and PAA films. The results showed that the wettability of the samples was affect by chemical interactions of functional groups on the surface deposited after plasma treatment. The effect of the porous surface morphology on wettability was not significant compared to the plasma treated films with new chemical interactions effects. / Neste trabalho foram investigadas as propriedades de molhabilidade das superfícies nanoestruturadas da alumina anódica porosa (AAP) modificadas por plasma. Os filmes de AAP foram produzidos sobre substrato de alumínio pelo método de anodização potenciostática em duas etapas em solução de ácido oxálico. Após a fabricação, as amostras foram submetidas a um tratamento a plasma (com oxigênio) ou a deposição a plasma (em HMDSO ou em uma mistura de HMDSO e argônio). Antes das modificações das superfícies, removeram-se as impurezas das amostras através de técnicas de limpeza a plasma. No tratamento a plasma, o gás oxigênio foi utilizado para a obtenção de superfícies hidrofílicas. Por outro lado, para tornar a superfície hidrofóbica ou menos hidrofílica, foram feitas duas séries de deposição a plasma, uma contendo uma mistura de argônio e HMDSO e outra série somente com HMDSO. O tratamento ou deposição a plasma também foram feitas em amostras de alumínio eletropolido, sem a camada de AAP, a fim de verificar a influência morfológica do substrato na molhabilidade. A caracterização morfológica dos filmes de AAP foi feita por microscopia eletrônica de varredura (MEV), onde foi verificada a formação dos poros na superfície. A caracterização microestrutural foi feita por espectroscopia de absorção no infravermelho por transformada de Fourier (FTIR) com o objetivo de verificar as alterações químicas na superfície. A molhabilidade foi analisada utilizando um goniômetro, equipamento que realiza medição direta do ângulo de contato. Os resultados mostram que a molhabilidade da superfície é afetada por interações químicas dos grupos funcionais na superfície dos filmes. Por outro lado, o efeito da morfologia sobre a molhabilidade da superfície não é significativo nas condições estudadas.

Submitted by Eliseu Antonio Cavalini null (cavaliniea1356@ig.com.br) on 2017-01-08T01:45:41Z No. of bitstreams: 1 Tese Dout V Final.pdf: 2360887 bytes, checksum: 17f60dc9305936e9dd9ea3744d049148 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-11T13:28:41Z (GMT) No. of bitstreams: 1 cavalini_ea_dr_guara.pdf: 2360887 bytes, checksum: 17f60dc9305936e9dd9ea3744d049148 (MD5) / Made available in DSpace on 2017-01-11T13:28:41Z (GMT). No. of bitstreams: 1 cavalini_ea_dr_guara.pdf: 2360887 bytes, checksum: 17f60dc9305936e9dd9ea3744d049148 (MD5) Previous issue date: 2016-12-09 / Plasmas de gases e / ou vapores orgânicos produzem filmes finos ou pós apresentando características poliméricas, especialmente quando os plasmas são derivados de monômeros das famílias dos hidrocarbonetos alcoóis, siloxanos, silazanos, e outro. Neste trabalho, os filmes finos foram obtidos a partir da mistura de ácido cítrico-etilenoglicol-metal complexador depositado a plasma, com 13,56 MHz de radiofrequência na potência de 10 a 50 W e pressão fixada a 10 Pa. Os resultados da análise de espectroscopia de infravermelho FTIR mostrou que os grupos vibracionais dos filmes estavam preservados, mas com modificações em suas estruturas moleculares. Foram observados nos resultados obtidos por espectroscopia fotoelétrica de raios-X modificações na composição química da ligação oxigênio-carbono e oxigênio-hidrogênio com variação da potência de 10 a 50 W. A taxa de deposição dos filmes finos diminuiu de 0,10 a 0,08 nm/minuto com o aumento da potência de 10 a 50 W. As propriedades óticas das amostras como o índice de refração, coeficiente de absorção, gap ótico foram investigados por espectroscopia UV- visível. Destas análises foram possíveis obter valores n de 1,54 a 1,50 e energia do gap entre 4,75 e 4,85 eV. A técnica de ângulos de contato e foi utilizada para investigar a molhabilidade das amostras, que apresentaram caráter hidrofílico em todas as condições de deposição dos filmes. A técnica de EDS foi usada para investigar as composições químicas das amostras. Além disso, os filmes obtidos apresentaram valores de condutividade elétrica superior a 10-8 (Ωcm)-1 e constantes dielétricas entre 2,4 e 2,7. / Plasmas from gases and / or organic vapors produce thin films or powders presenting polymeric characteristics, especially when the plasmas are derived from monomers of the families of hydrocarbons, alcohols, siloxanes, silazanes, and others. In this work, thin films were obtained by citric acid / ethylene glycol / complex metal deposited by 13.56 MHz RF plasma at 10 and 50 W fixed pressure 10 Pa. FTIR spectroscopy showed that the main vibrational groups of the films were preserved, but with modifications in their molecular structures. It was observed by X –ray photoelectron spectroscopy chemical composition modifications in oxygen – carbon and oxygen – hydrogen bond while the deposition power changed from 10 to 50 W. The deposition rate of the samples decreased from 0.10 to 0.08 nm / minute while the RF power increases from 10 to 50 W. The samples optical properties as refractive index n, absorption coefficient, optical gap Eg were investigated by UV – Visible spectroscopy. From these analysis were possible to obtain values of n from 1.54 to 1.50 and Eg between 4.75 and 4.85 eV. Contact angle and surface energy measurements were used to investigate the wettability of composite Polymer films, for all depositions conditions the films presented hydrophilic character. EDS was used investigate components of the samples. Moreover, the film showed electrical conductivity values greater than 10-8(Ωcm)-1 and dielectric constant between 2.2 and 2.7.

This PhD project investigated the ramifications of air-cured and nitrogen-cured manufacturing processes during silicone hydrogel contact lens manufacture in terms of lens surface characterisation and clinical performance. A one-hour contralateral clinical study was conducted for ten subjects to compare the clinical performance of the two study lenses. The main clinical findings were reduced levels of subjective performance, reduced surface wettability and increased deposition. Contact angle analysis showed the air-cured lenses had consistently higher advancing and receding contact angle measurements, in comparison with the nitrogen-cured lens. Chemical analysis of the study lens surfaces in the dehydrated state, by x-ray photoelectron spectroscopy (XPS) and time-of-flight mass spectrometry (ToF-SIMS), showed no difference due to surface segregation of the silicone components. Analysis of frozen lenses limited surface segregation and showed a higher concentration of silicone polymer components and lower concentration of hydrophilic polymer components at the surface of the air-cured lens, in comparison with the nitrogen-cured lens. Scanning electron microscope (SEM) imaging showed the nitrogen-cured lens to have a surface typical of a hydrogel material, whereas the air-cured lens had regions of apparent phase separation. In addition, atomic force microscopy (AFM) showed the air-cured lens to have a rougher surface associated with greater adherence of contaminants (often observed in materials with reduced polymer cross-linking). In conclusion, clinical assessment of the study lenses confirmed the inferior performance of the air-cured lens. Surface analysis suggested that the non-wetting regions on the air-cured lenses were associated with elevated level of silicone components, reduced polymer cross-linking and polymer phase separation.

La récupération du pétrole par injection d’eau douce (LSW) a pour but de récupérer les huiles résiduelles piégées dans les réservoirs. Après des preuves d’une augmentation du taux de récupération lors de la LSW, des résultats controversés ont émergé et les mécanismes proposés dans la littérature font toujours l’objet de débat. Il est donc essentiel d'avoir une compréhension approfondie des interactions huile/saumure/roche (COBR) afin d’éclaircir les mécanismes engendrés par cette technique. Nous avons procédé en faisant une étude de la mouillabilité à l'eau des différentes argiles gonflantes en fonction des cations échangeables (Li+, Na+, K+ et Ca2+), de l'humidité relative, de la taille des particules et de la rugosité de la surface. Même si ces paramètres ont été étudiés séparément, la nature des cations, la rugosité de surface et la taille des particules sont étroitement liées. La nature du cation échangeable conduit indirectement l'état de rugosité des films d'argile cependant, c'est l'énergie d'hydratation qui entraine les angles de contact. D'autre part, pour une argile donnée avec un cation échangeable donné, la mouillabilité du film a été observée comme étant influencée par la taille des particules. Plus la taille des plaquettes d'argile est importante, plus le film est rugueux et plus l'angle de contact est élevé. En ce qui concerne l'influence de l'humidité relative, elle n'a eu qu’un effet marginal sur les angles de contact. Cependant, en travaillant à haute humidité le phénomène d'évaporation a été limité. En ce qui concerne la mouillabilité à l'huile des minéraux argileux, à une interface solide/huile/air, l'huile s’est rapidement étalée lors qu’elle a été déposée sur les différents minéraux. Dans la deuxième partie de la thèse, l'interaction biphasique huile/milieu aqueux a été étudiée par des mesures de tension interfaciale (IFT) en fonction de différents sels et de leurs concentrations. Les résultats obtenus avec deux huiles brutes et un système modèle (dodécane contenant de l'acide oléique) ont montré que l'IFT est minimum à une salinité optimale. En ce qui concerne les espèces de sel, un abaissement de l'IFT des huiles brutes a été observé en présence des cations petits, durs et fortement polarisants (tels que le Li+, Mg2+ et Ca2+) et en présence de cations gros, mous et fortement polarisables (tels que Rb+ et Cs+). Les résultats sur le système modèle ont montré que l'abaissement de l'IFT était dû aux interactions entre les petits cations qui sont durs et la tête polaire dure du tensioactif (oléate). La troisième partie de la thèse a été consacrée à l'étude des interactions triphasique huile/saumure/argile. Nos résultats montrent d'abord que, dans des conditions qui favorisent le « salting-in » des tensioactifs, l'adsorption des composants du pétrole brut sur les minéraux argileux a été favorisée (abaissement des angles de contact de l'huile sur les surfaces de mica en présence de saumure composée de cations divalents). L'interaction triphasique a également été étudiée par la stabilité des émulsions en présence des colloïdes d'argiles. Selon les différentes observations, nous avons émis l'hypothèse que certains composants de pétrole brut s'adsorbent directement sur des surfaces minérales tandis que d'autres ont besoin d'un pont cationique (Na+, Ca+ ou Mg2+) / The technique of low salinity waterflooding (LSW) during Enhanced Oil Recovery (EOR) processes, attempt to recover residual oils trapped in petroleum reservoirs. So far, after evidences of the benefits of LSW, some controversial results emerged and the mechanisms underlying the technology is still debated in the literature. It thus appears crucial to have a thorough understanding crude oil/brine/rock (COBR) interactions as the reservoir is a porous medium in which solid and fluid phases coexist. Firstly we studied the water wettability of different swelling clay minerals as a function of different interlayer cations (Li+, Na+, K+ and Ca2+), relative humidity, particle size and surface roughness. Even if these parameters have been investigated individually, the nature of the cations, surface roughness and particle size are closely linked. The nature of exchangeable cation indirectly drives the state of roughness of the clay films (in decreasing order: Ca2+ >>> K+ > (Li+, Na+)). However, it is the hydration energy which ultimately takes over during contact angle measurements. On the other hand, for a given clay mineral with a given exchangeable cation, wettability of the film has been observed to be influenced by the size of the particles. The larger the size of the clay platelets, the rougher the film and the higher the contact angle. As far as the influence of relative humidity is concerned, it only has a marginal effect on the contact angles. However, working at high humidity has shown to limit the phenomenon of evaporation. Regarding the oil wettability of clay minerals, at a solid/oil/air interface, the oil rapidly spread on the different clay minerals. In the second part, biphasic oil/aqueous medium interaction as a function of salt species and concentration has been studied via interfacial tension measurements (IFT). The results obtained with two crude oils and a model system (dodecane containing oleic acid) have shown that IFT is minimum at an optimum salinity. As far as salt species is concerned, IFT of the crude oils has been observed to be low in the presence of small, hard and highly polarising ions like Li+, Mg2+ and Ca2+ and in the presence of large, soft and highly polarisable ions like Rb+ and Cs+. The results on the model system has shown that lowering of IFT was due to ion paring between the small, hard cations and the hard polar headgroup of the surfactant (oleate). The third part of the thesis was dedicated to the study of triple phase oil/brine/clay interactions. Our results firstly show that in conditions favouring salting-in of surfactants, adsorption of crude oil components on clay minerals have been favoured (lowering of oil contact angles on mica surfaces in the presence of brines composed of divalent cations). Triple phase interaction has also been investigated by studying the stability of emulsions in the presence of clay colloids.According to the different observations we hypothesised that some crude oil components adsorb directly onto mineral surfaces while others need a cation bridge (Na+, Ca+ or Mg2+).

Ce présent travail de thèse porte sur l’étude du potentiel d’un traitement de surface par laser femtoseconde comme étape de substitution aux traitements réalisés actuellement lors de la métallisation de polymère. Pour cela, l’étude des modifications chimiques et morphologiques induites par traitement laser femtoseconde ainsi que leurs influences respectives sur les propriétés d’adhérences et de mouillabilités de la surface polypropylène sont présentées. Une revue bibliographique met en évidence la faisabilité d’une modification contrôlée de la surface du polypropylène après traitement laser femtoseconde. De plus, ces modifications engendrent une évolution démontrée des propriétés de mouillage qui peuvent répondre à certaines demandes industrielles. Après traitement laser femtoseconde, la surface traitée répond de différentes manières à la sollicitation en fonction de ses propriétés intrinsèques. Les expériences d’impacts localisés et de surfaces nous ont conduits à observer trois stades de modifications topographiques pour les conditions étudiées : un phénomène d’incubation, d’accumulation et d’ablation. Ce dernier a fait l’objet d’une étude plus approfondie. De manière générale, on observe deux régimes d’ablation linéaires pour l’ensemble des densités de puissance étudiées lorsque l’on étudie la profondeur d’ablation en fonction du nombre d’impulsion et le volume d’ablation en fonction de la densité de puissance cumulée. Enfin, nous montrons que les liaisons présentes en surface après traitement sont dépendantes de deux facteurs ; la densité de puissance cumulée utilisée et l’environnement de travail. Sachant que les modifications topographiques obtenues sont de types multi-échelles, les résultats ont été analysés sur la base des modèles de Wenzel (1936) et de Cassie-Baxter (1944) relatifs à la théorie du mouillage de surfaces rugueuses. Les résultats expérimentaux et leurs corrélations avec les paramètres de rugosités 3D calculés à différentes échelles ont été traités par une analyse statistique. On observe alors un comportement mixte avec un contact intime de la goutte sur les sommets des aspérités (modèle de Wenzel) et un contact hétérogène (airpolypropylène) à une échelle mésoscopique (état « fakir » décrit par le modèle de Cassie-Baxter). Toutefois, la situation où la goute repose sur le sommet des structures (CB) n’est pas toujours stable. Nous avons étudié la transition de l’état CB à l’état W par des expériences d’évaporation. On observe que cette transition est fortement dépendante de la chimie de surface dont la contribution est prépondérante sur les propriétés d’adhérence métal/PP. En contrôlant cette propriété, il est alors possible de répondre à une problématique industrielle de galvanoplastie (adhérence augmenté par le traitement laser) ou d’électroformage (adhérence faible permettant une réplication de bonne qualité des motifs). / This work presents the potential of a femtosecond laser surface treatment as an alternative step of pretreatments during the metallization of polymer. To do this, the study of chemical and morphological modification induced by femtosecond laser treatment and their respective influences on the properties of adhesion and wettability of polypropylene surface are presented. A literature review highlights the feasibility of a controlled surface modification after femtosecond laser treatment of polypropylene (PP). In addition, it is known that these modifications changes the wetting properties and can be used to meet industrial applications development. After femtosecond laser treatment, the treated surface responds to the solicitation with different morphological comportment according to its intrinsic properties. Experiences of localized impacts and surfaces us to observe three stages of topographic changes to the conditions studied: an incubation phenomenon of accumulation and ablation. The ablation phenomenon is further study. Generally, two linear ablation regime is observed for all power densities examined when considering the depth of ablation as a function of the pulse number and the ablation volume according to the accumulated power density. Finally, we show that the bonds present on the surface after treatment are dependent on two factors: the accumulated power density used and the working environment. Knowing that topographic obtained is multi-scales, the results were analyzed on the basis of models Wenzel (W)(1936) and Cassie–Baxter (CB) (1944) which explain the theory of wetting of rough surfaces. The experimental results and their correlations with 3D roughness parameters calculated at different scales were treated by statistical analysis. We observe a mixed model behavior with intimate contact of the drop on the tops of the asperities (Wenzel model) and a heterogeneous contact (air - PP) in a mesoscopic scale (state " fakir " described by the Cassie -Baxter model). However, this situation where the drop sits on the top of asperities (CB) is not always the most stable. We have studied the transition between the CB state and the W state by evaporation experiments. It is observed that this transition is strongly dependent on the surface chemistry whose contribution is much greater than the adhesion properties metal / PP. If controlling this property, it is possible to obtain two industrial applications: electroplating (increased adhesion by laser treatment) or electroforming (low adherence to replicate the topography).

Dans ce travail de thèse, la texturation de surface d‟alliages de titane a été étudiée en utilisant un procédé d'écriture directe par laser femtoseconde dans le but d'améliorer la mouillabilité d‟implants dentaires et orthopédiques par les fluides biologiques et la minéralisation de la matrice (formation osseuse) tout en réduisant l'adhésion bactérienne et la formation de biofilmes. Des surfaces de titane (Ti-6Al-4Vet cp Ti) ont été micro-, nano-texturées par laser femtoseconde et une biofonctionnalisation de ces surfaces a été ajoutée ou non par greffage de peptides d'adhésion cellulaire (peptides RGD) en surface de ces différents matériaux. Les textures de surface peuvent être classées comme suit: (a) structures périodiques de surface induites par laser (LIPSS); (b) étalage de nanopiliers (NP); (c) étalage de micro colonnes recouvertes de LIPSS (MC-LIPSS) formant une distribution bimodale de rugosité. Nous avons montré que la texturation de surface par laser améliore la mouillabilité des surfaces avec de l'eau ainsi qu‟une solution saline tamponnée Hank's (HBSS) et amène une anisotropie de mouillage. Une minéralisation cellulaire est observée pour toutes les surfaces des deux alliages de titane lorsque des Cellules Souches Mésenchymateuses humaines (hMSC) sont cultivées dans un milieu ostéogénique. La minéralisation de la matrice et la formation de nodules osseux sont considérablement améliorées sur les surfaces texturées LIPSS et NP. Parallèlement,l'adhésion de Staphylococcus aureus et la formation de biofilmes sont considérablement réduites pour les surfaces texturées LIPSS et NP. La biofonctionnalisation des différentes surfaces texturées (cp Ti) par laser a été réalisée et caractérisée par spectroscopie de photoélectrons (XPS) et par microscopie à fluorescence en utilisant des peptides fluorescents. L‟ensemble des résultats obtenus suggèrent que la texturation de surface d'alliages de titane (Ti-6Al-4V et cp Ti) en utilisant une technique d‟écriture directe par laser femtoseconde est un procédé prometteur pour l'amélioration de la mouillabilité de la surface d'implants dentaires et orthopédiques par les fluides biologiques et leur ostéointégration (différenciation ostéoblastique et minéralisation de la matrice), tout en réduisant l‟adhésion de Staphylococcus aureus et la formation de biofilmes. Enfin, la combinaison de la texturation par laser et du greffage covalent d‟un principe actif (ici un peptide d‟adhésion cellulaire comme le peptide RGD) amènera indéniablement une bioactivité utile pour favoriser l'adhésion des hMSC et faciliter laformation osseuse. / In the present thesis the surface texturing of Ti alloys using femtosecond laser direct writing method is explored as a potential technique to enhance the wettability of dental and orthopaedic implants by biological fluids and matrix mineralisation (bone formation), while reducing bacteria adhesion and biofilmformation. The surface texture was combined with biofunctionalisation by covalent grafting of a RGD peptide sequence as well. The surface textures can be classified as follows: (a) Laser-Induced Periodic Surface Structures-LIPSS; (b) nanopillars arrays(NP); (c) arrays of microcolumns covered with LIPSS (MC-LIPSS), forming a bimodal roughness distribution. Laser texturing enhances surface wettability by water andHank‟s balanced salt solution (HBSS) and introduces wetting anisotropy, crucial incontrolling the wetting behaviour. Matrix mineralisation is observed for all surfaces of both Ti alloys when human mesenchymal stem cells (hMSCs) are cultured in osteogenic medium. Matrix mineralisation and formation of bone-like nodules are significantly enhanced on LIPSS and NP textured surfaces. On the contrary, Staphylococcus aureusadhesion and biofilm formation are significantly reduced for LIPSS and NP textured surfaces. The biofunctionalisation of the laser textured surfaces of cp Ti is sucessfully achieved. In general, these results suggest that surface texturing of Ti alloys using femtosecond laser direct writing is a promising method for enhancing surface wettability of dental and orthopaedic implants by biological fluids and their osseointegration (osteoblastic differentiation and matrix mineralisation), while reducing Staphylococcus aureus adhesion and biofilm formation. Finally, the combination of laser texturing and covalent grafting of a RGD peptide sequence may be potentially useful for increasing cell adhesion and facilitating bone formation.

Des carbones dérivés de carbures à porosité monodisperse et nanocentrée autour de 0,6 nm ont été préparés par fluoration de carbures via l’arrachement sélectif de l’élément métallique et le maintien de l’empreinte carbonée initiale. Les carbures précurseurs ont été choisis parmi deux des classes de carbures à savoir interstitiels pour le carbure de titane et de niobium et covalents pour le carbure de silicium. La fluoration directe procédant sous flux d’une atmosphère de fluor pur apparait comme étant la seule méthode de fluoration apte à déstabiliser les poudres cristallisées. Appliquée au carbure de titane, des matériaux à teneur variable en carbone et en trifluorure de titane ont été obtenus et caractérisés structuralement par Diffraction des Rayons X quantitative, spectroscopies IR et Raman et leur texture sondée par Microscopie Electronique à Balayage et à Transmission et isothermes d’adsorption à l’azote à 77K. Ils ont aussi été évalués comme matériau d’électrode de supercondensateurs. La fluoration du carbure de silicium pour la stabilisation d’une phase carbonée est plus difficile et seule l’abaissement de la cristallinité du carbure par l’utilisation d’une mise en forme de type couche mince combinée à une méthode de fluoration alternative par décomposition de l’agent fluorant XeF2 ont permis d’obtenir une couche mince de carbone nanostructurée valorisable comme lubrifiant solide et aux propriétés de mouillabilité modulables. / Carbide-derived Carbons (CDC) with monodisperse ultramicroporosity have been prepared by carbide fluorination thanks to selective etching of metallic element. The chosen carbides precursors were titanium and niobium carbides, and silicon carbides from interstitial and covalent carbide family, respectively. Direct fluorination proceeding by a pure flow of 1 atm. of molecular fluorine is the only fluorination way which leads to the transformation of the powdered and highly crystallized carbide into some carbons. Materials with different ratio of carbon and solid titanium trifluoride were successfully obtained by direct fluorination of titanium carbide, characterized by quantitative XRD, IR and Raman spectroscopies and Scanning and Transmission Electronic Microscopies and used in supercapacitors. The direct fluorination of silicon carbide in order to form carbon is more difficult because of the competition between carbon formation and its degradation into gaseous carbon fluorides. To success in our goal, thin film morphology was used as precursor. However, an accurate fluorination way is needed and decomposition of XeF2 fluorinating agent was chosen. Thin films with variable thickness of nanostructured carbon at the surface were obtained and used as solid lubricant with tunable wettability properties.

Avec une population toujours croissante et la pénurie de plus en plus importante des ressources en eau douce, l’humanité s’est tournée vers les océans pour ses besoins en eau potable. Afin de faire face aux limites des procédés conventionnels de dessalement d’eau de mer, la distillation membranaire (DM) connaît un intérêt croissant. Même si l’intérêt envers la DM pour le dessalement d’eau de mer est apparu au cours des dernières décennies, aujourd’hui le risque de mouillage des membranes est l’un des obstacles majeurs à son développement industriel. Dans le cadre du projet ANR « WETMEM», l’objectif de cette thèse est de développer des outils de compréhension des mécanismes de mouillage en distillation membranaire sous vide. Plusieurs membranes, fabriquées par des partenaires du projet WETMEM, et commerciales ont été étudiées afin de comprendre l’influence des propriétés des membranes sur les indicateurs de mouillabilité. De plus, une définition et une classification des mécanismes de mouillage ont été proposées. Par la suite, deux indicateurs de mouillage ont été développés à l'aide de la microscopie électronique à balayage et de la spectroscopie de dispersion de rayons X selon une méthode appelée « Détection d'intrusion de traceur dissous ». Une preuve de concept a été fournie, dans laquelle différents mécanismes de mouillage ont pu être visualisés et interprétés. Ces indicateurs ex situ ont alors été utilisés avec des indicateurs de mouillabilité (Angle de contact, Pression d’intrusion de liquide) afin de comprendre l’influence de la température (35-50 ° C), de la salinité (22-310 g / L de NaCl sol.) et du débit (400 - 4000 Re) sur le mouillage et la mouillabilité d'une membrane de PVDF en distillation membranaire sous vide. Il a alors été constaté que la salinité a l’impact le plus important sur le mouillage par rapport aux autres paramètres de fonctionnement. En outre, un outil optique in-situ non invasif a été développé. Il permet de visualiser le mouillage in-situ en distillation membranaire. La progression du mouillage in situ a été observée à différentes échelles et pour différentes solutions salines et eaux de mer. / With an ever-increasing population and the growing disparity in potable water resource, humanity has turned its attention to the oceans for its potable water needs. To overcome the current limitations in current desalination technologies, membrane distillation (MD) is actively being developed. The interest of MD for seawater desalination was established in the last decades but today the risk of membrane wetting is one of the major barrier for industrial implementation of MD. Under the framework of the ANR project “WETMEM”, the issue of this thesis was to develop tools for better understanding wetting mechanisms in vacuum membrane distillation. Several fabricated (WETMEM partners) and commercial membranes were studied to understand the influences of membrane properties on wettability. Therefore, a definition and classification on wetting were formulated. After that two wetting indicators were developed using scanning electron microscopy and X-ray dispersion spectroscopy under a method called “Detection of Dissolved Tracer Intrusion”. A proof of concept was provided with various wetting mechanisms visualized and interpreted. These ex-situ indicators were used with wettability tools (Contact Angle, Liquid Entry Pressure) to understand the influence of temperature (35-50°C), salinity (22-310 g/L NaCl sol.) and flow rate (400 – 4000 Re) on wetting and wettability of a PVDF membrane under vacuum membrane distillation. Indeed, it was found that salinity has a greater impact on wetting than the other operating parameters. Additionally, a proof of concept was provided for non-invasive in-situ optical method for visualizing wetting in membrane distillation. Progression of in-situ wetting visualization was validated at different scales for various saline solutions and seawaters.

This work deals with the metal surface wetting problems of molten lead-free solder and monitoring of ongoing processes at the inter-phase interface using the method of evaluation of the height of the molten solder deducted from the video sequences. The work is aimed at evaluating the metal surface wettability, wetting angle determined. Wettability of the metal surface is compared for different types of surface treatments and for different ages of the measured samples. Measurement is performed at the improved workplace, is used to evaluate the newly derived formula for calculating the wetting angle and created program for automatic evaluation of Picture is used to.