Research activities towards the self-assembly of small organic molecules building blocks which lead to form supramolecular gel has increased extensively during the past two decades. The fundamental investigations of the morphological properties and the mechanical properties of these supramolecular gels are crucial for understanding gelation processes. Most supramolecular gelators were discovered by serendipity, but nowadays ratiional design of new gelators has become somewh at feasible. As a consequence, an increasing number of multi stimuli-responsive and functional molecular gels are reported, offering great prospects with myriads of applications includ ing drug delivery and smart materials as shown in scheme 1. Scheme 1 Part 2: Synthesis of semiconductor nanocrystals In the last two decades, the synthetic development of semiconductor col loidal nanocrystals has been extended from the adjustment of their size, shape, and composition of the particles at the molecular level. Such adjustments of nanocrystals at the molecula r level might open different fields of applications in materials and biological sciences. I n this chapter, the concept of the shape contr ol synthesis of colloidal nanocrystals with a narrow size distribution, and the synthesis of composition dependent alloy type mat erials are described (Scheme 2). Scheme 2 Chapter 2: Synthesis of luminescent semiconductor nanocrystals Part 1: Cadmium deoxycholate: a new and efficient precursor for high ly luminescent CdSe nanocrystals This part demonstrates the sy nthesis of Cadmium deoxycholate (CdDCh2), an efficient Cd-precursor for the synthesis of high quality, monodisperse, multi color emittting CdSe Scheme 3 nanocrystals, while maintaining their high photoluminescent quantum efficiency (Scheme 3). The high thermal stability of CdDCh2 (decomposition temperature: 332 °C) was utilized to achieve high injection and growth temperatures (∼300 °C) for the syntheesis of red emitting nanocrystals with a sharp f ull width at half maximum (FWHM) and multiple excitonic absorption features. We believe that CdDCh2 can be useful for the prreparation of other nanomaterials such as CdS, CdTe and CdSe@CdS core-shell QDs. Part 2: Ligand mediated exccited state carrier relaxation dynamics of Cd1-xZnxSe1-ySy NCs derived from bile salts Bile salts of Cadmium and Zinc provide a convenient and inexpensive single step synthetic route for highly photoluminescent and stable semiconductor nanocrystals (NCs). The high thermal stabilities of Cadmium and Zinc deoxycholates (CdDCh2 and ZnDCh2) allowed us to fine-tune the synthesis of the NCs at high temperatures while maintaining the monodispersity, crystallinity and reproducibility (Scheme 4). Organic capping agent induced lattice strain affects the excited Scheme 4 state relaxation processes of the NCs. The analysis of photoluminescence decay profiles revealed that the average lifettime decreased with the increasing lattice strain of the NCs. A kinetic stochastic model of photoexcited carrier relaxation dynamics of NCs was employed to estimate the values of the radiative recombination rates, the photoluminescence quenching rates and the non-radiative recombination rates of the NCs. These data showed that the non-radiative relaxation rates and the numbeer of surface trap states increased with the incrreasing lattice strain of the NCs. Such types of NCs can have great potential in nonlinear optics, photocatalysis and solar cells. Chapter 3: Synthesis of organic-inorganic hybrid materials Part 1: Hierarchical self-assembly of photoluminescent CdS nanoparticles into bile acid derived organogel: morphological and photophysical properties In this part a strategy towards integrating photoluminescent semiconductor nanoparticles into a bio-surfactant derived organoggel has been reported. A facially amphiphilic bile thiol was used for capping CdS nanoparticless (NPs) which were embedded in a gel derived from a new bile acid organogelator in order to furnish a soft hybrid material (Scheme 5). The presence of CdS NPs in a well-ordered 1D array on the organogel network was confirmed using microscopic Scheme 5 techniques. Photophysical stuudies of the gel–NP hybrid revealed resolved excitation and emission characteristics. Time resolved spectroscopic studies showed that the average lifetime value of the CdS NPs increased in the gel state compared to the sol phase. A kinetic model was utilized to obtain quantitative information about the different decay pathways of the photoexcited NPs in the sol and gel states. Part 2: A novel strategy towards designing a CdSe quantum dot–metallohydrogel composite material This section describes an efficiient method to disperse hydrophobic CdSe quaantum dots (QDs) in an aqueous phase using cetyltriimethylammonium bromide (CTAB) micelles without any surface ligand exchange. The water soluble QDs were then embedded in the 3D self-assembled fibrillar networks (SAFINs) of a hydrogel showing homogeneous dispersibility as eviidenced by Scheme 6 optical and electron microscopico techniques (Scheme 6). The photophyssical studies of the hydrogel–QD from composite are reported for the first time. These composite materials may have potential applications in biology, optoelectronics, sensors, non-linear optics and materials science. Part 3: Photophysical aspectts of self-assembled CdSe QD-organogel hyybrid and its thermoresponsive properties A luminescent hybrid gel was constructed by incorporating CdSe quantuum dots (QDs) in a facially amphiphilic bile acid derived dimeric urea organogel throough non-covalent interaction between ligands capped on QDs surface and hydrophobic pockets of the gel (Scheme 7). The optical transparency of the hybrid materials and the dirrectionalities of the QDs in the gel medium were confirmed by photophysical and microscopic studies. The detailed excited state dynamics of the QD–organogel hybrid has been reported for the first time with the help of lifetime analysis and a kinetic decay model, and thee data revealed that the average lifetime of the QDs decreased in the gel medium. The reversible thermoresponsive behavior of the QD doped organogel was investigated by steady-state fluorescence spectroscopy. W e believe that the results obtained herein provides a route to develop a thermoresponsive system for practical application, especially because of the spatial assembly between soft organic scaffolds and colloidal QDs. Scheme 7 Part 4: In-situ formation of luminescent CdSe QDs in a metallohydrogel: a strategy towards synthesis, isolation, storage and re-dispersion of the QDs A one step, in-situ, room temperature synthesis of yellow luminesce nt CdSe QD was achieved in a metallohydrog el derived from a facially amphiphilic bile salt, resulting in a QD-gel hybrid (Scheme 8). T he ordered self-assembly and homogeneous distribution of the CdSe QDs in the hydrogel network was observed from optical and electro n micrographs. The different excited state behav iors of the hybrid were revealed for the fir st time using time resolved spectroscopy. Ad ditionally, we described the successful isolation of the photoluminescent CdSe QDs from the gel followed by their re-dispersion in an organic solvent using suitable capping ligands. Scheme 8 Chapter 4: Facially a mphiphilic bile acid derived meta llohydrogel: an efficient template for th e enantioselective Diels-Alder reactio n An enantioselective Diels-Ald er reaction mediated by a facially amphiphilic bile acid derived metallogel scaffold has been a chieved (Scheme 9). Different hydrophobic domains present in Scheme 9 the gel appear to facilitate the enantioselective reaction. Various spectro scopic and electron microscopic techniques were employed to understand the possible reasons for the stereoselectivity in the gel. Subsequently, different counter anion s dependent rate accelerations and induced enantioselectivity in the ZnCh2 gel were studied in detail. These preliminary results of the non-covalent based supramolecular heterogeneous catalysis offer new possibilities for using metallogels as nanoreactors for different stereoselective reactions.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-26T19:38:51Z No. of bitstreams: 1 POLYANA TARCIANA ARAÚJO DOS SANTOS – TESE (UAEMa) 2015.pdf: 2974694 bytes, checksum: 08e52baa2c42ce5e7b0e35cbf00934bd (MD5) / Made available in DSpace on 2018-06-26T19:38:51Z (GMT). No. of bitstreams: 1 POLYANA TARCIANA ARAÚJO DOS SANTOS – TESE (UAEMa) 2015.pdf: 2974694 bytes, checksum: 08e52baa2c42ce5e7b0e35cbf00934bd (MD5) Previous issue date: 2015-01-29 / CNPq / Neste trabalho de pesquisa foi obtido um material híbrido a base de nanoferritas Ni0,5Zn0,5Fe2O4 e CoFe2O4 modificada a superfície com agente silano e funcionalizadas com quitosana visando seu uso como biossensores. Para este fim, as nanoferritas foram sintetizadas por reação de combustão e silanizadas com o 3-aminopropiltrimetoxissilano. A funcionalização foi realizada pelo método de evaporação do solvente usando o biopolímero quitosana. Todas as amostras foram caracterizadas por difração de raios X, espectrometria de infravermelho por transformada de Fourier, espectroscopia por energia dispersiva de raios X, análise termogravimétrica, microscopia eletrônica de varredura, microscopia eletrônica de transmissão, teste de sedimentação e separação magnética, medidas magnéticas e análise in vitro por citotoxidade. As amostras como sintetizadas apresentaram a formação da fase única do espinélio em estudo com característica nanométrica e após a formação do híbrido a estrutura do material foi mantida. Nos espectros de infravermelho observaram-se bandas de absorção características das nanoferritas e bandas referentes à presença do agente silano e da quitosana. Por meio das micrografias observou-se a formação de aglomerados de aspecto frágil, e após silanização e funcionalização observou-se uma morfologia com aglomerados de aspecto mais rígido constituídos de nanopartículas fortemente ligadas. A análise termogravimétrica mostrou que as nanoferritas apresentaram baixa perda de massa e que após formação do híbrido houve um aumento da perda de massa comprovando assim, a presença do agente silano e da quitosana. Quanto ao comportamento magnético, ambas as nanoferritas apresentaram elevada magnetização de saturação típica de materiais ferrimagnéticos, este comportamento foi mantido após formação do híbrido sendo adequado para aplicações biotecnológicas. A viabilidade celular das nanoferritas mostrou característica citotóxica para a ferrita Ni0,5Zn0,5Fe2O4 e não citotóxica para a ferrita CoFe2O4, a formação do híbrido favoreceu aumento da viabilidade celular em ambas as nanoferritas. Os materiais híbridos obtidos são promissores para o uso na nanobiotecnologia como biossensores e/ou em tratamento como diagnóstico clinico. / In this research was obtained a hybrid material nanoferrit es base Ni0,5Zn0,5Fe2O4 and CoFe2O4 modified the surface with silane agent and functionalized chitosan aiming their use as biosensors. To this end, nanoferritas were synthesized by combustion and silanized with 3-aminopropyltrimethoxysilane. The functionalization was carried out by the solvent evaporation method using the biopolymer chitosan. All samples were characterized by X-ray diffraction, infrared spectroscopy by Fourier transform spectroscopy energy dispersive X-ray, thermal analysis, scanning electron microscopy, transmission electron microscopy, sedimentation test and magnetic separation, magnetic measurements and Analysis by in vitro cytotoxicity. The samples showed synthesized as the formation of spinel single phase with nanometer feature under study and after the formation of the hybrid structure of the material has been maintained. In the infrared spectra there were absorption bands characteristic of nanoferritas and bands related to the presence of the silane agent and chitosan. Through micrographs showed the formation of agglomerates frail and after silanization and functionalization was observed with a morphology more rigid aspect of tightly bound agglomerates of nanoparticles. Thermogravimetric analysis showed that the nanoferritas showed low weight loss and that after hybrid formation was increased mass loss thereby proving the presence of the silane agent and chitosan. As for the magnetic behavior, both nanoferritas had high magnetization typical saturation ferrimagnetic materials, this behavior continued after the hybrid formation is suitable for biotechnological applications. Cell viability nanoferritas showed characteristic for cytotoxic and non-cytotoxic ferrite Ni0,5Zn0,5Fe2O4 to CoFe2O4 ferrite, the formation of hybrid favored increased cell viability in both nanoferritas. The obtained hybrid materials are promising for use in nanobiotechnology as biosensors and / or treatment and clinical diagnosis.

A versatilidade das espumas poliuretanas permite sua aplicação em inúmeros setores industriais, devido à possibilidade de se obter diferentes conjuntos de propriedades apenas alterando sua formulação básica. Um tipo recorrente de alteração é a incorporação de diferentes tipos de fibras em matrizes de poliuretano, vastamente estudada com o objetivo de gerar materiais compósitos com melhores propriedades mecânicas do que a matriz original. Inúmeros autores reportaram a utilização de celulose cristalina como uma alternativa renovável aos agentes de reforço e revelaram que a celulose utilizada como aditivo em matrizes poliméricas afetou as propriedades mecânicas da matriz original e, em menor escala, exerceu influência sobre a estabilidade térmica do compósito. O presente trabalho dedicou-se a isolar a celulose cristalina contida nas fibras de bananeira mediante tratamento com ácido acético concentrado. Os tratamentos químicos são necessários para modificar a superfície do material e melhorar a adesão do agente de reforço à matriz. Tendo em vista os resultados associados à estabilidade térmica dos compósitos de poliuretano reforçados com celulose, buscou-se sintetizar materiais híbridos de celulose e MgO.nH2O. Foi observado que, mesmo em pequenas quantidades, a presença do óxido hidratado de magnésio afetou significativamente a estabilidade térmica do HB 98:2. Estudos térmicos indicam que os materiais compósitos estudados apresentaram comportamento semelhante ao da matriz PU. Estudos das propriedades compressivas dos materiais poliméricos gerados mostraram que a incorporação do HB 98:2 ao PU afetou positivamente as propriedades mecânicas do material, sendo que o compósito PU + 1 HB 98:2 apresentou desempenho mecânico superior ao da matriz pura. / The versatility of polyurethanes foams allows its application in numerous industries because of the possibility of obtaining different sets of properties just by changing its basic formulation. A recurrent type of modification is the incorporation of different types of fibers in polyurethane matrices widely studied with the objective of generating composite materials with better mechanical properties than the original matrix. Numerous authors have reported the use of crystalline cellulose as a renewable alternative to fillers and showed that the cellulose used as additive in polymer matrices affect the mechanical properties of the original matrix and, to a lesser extent, influence upon thermal stability of the composite. This work was dedicated to isolate the crystalline cellulose contained in banana fibers by treatment with concentrated acetic acid. The chemical treatments are needed to modify the surface of the material and improve adhesion of the filler to the matrix. In view of the results associated with the thermal stability of the composite polyurethane reinforced with cellulose, sought to synthesize hybrid materials cellulose and MgO.nH2O. It has been observed that even in small quantities, the presence of hydrated magnesium oxide significantly affect the thermal stability of HB 98: 2. thermal studies indicate that the studied composites showed similar behavior to the PU matrix. Studies of the compressive properties of polymeric materials generated showed that the incorporation of HB 98: 2 to PU positively affect the mechanical properties of the material, and the composite PU + HB 98 1: 2 had mechanical performance superior to that of pure matrix.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Zinc oxide (ZnO) microparticles with a star-shaped morphology have been synthesized by a novel and simple room-temperature method and decorated with gold (GNP) and silver (SNP) nanoparticles for enhanced photocatalysis and bactericide applications. The presence of thiourea during the precipitation of ZnO in alkaline conditions allowed the control of morphological features (e.g. average size and shape) and the surface functionalization with thiocyanate ions (SCN-). TEM images of the sample prepared at pH 12 suggest that the particles grow according to the oriented attachment mechanism. The emission spectra of these particles showed an interesting feature: the emission band position can be tunable by changing the excitation wavelength. SNPs and GNPs were prepared onto ZnO surface by a photoreduction method and it was found that their sizes can be easily controlled by changing the ZnO/AgNO3 or ZnO/HAuCl4 ratios. The presence of SCN- on the semiconductor surface prevents uncontrollable growth of Ag nanoparticles into different morphologies and high degrees of polydispersity. XRD, SEM, TEM, FTIR, UV-vis-NIR and PL were employed for characterizing the structure, morphology and optical properties of asobtained pure and hybrid nanostructures. Finally, the hybrid ZnO/Ag particles show plasmon-enhanced performance for applications in photocatalysis and antibacterial activity than the pure ZnO counterpart. In this work, it was studied the photodegradation of an aqueous methylene blue solution under UV-A irradiation and antibacterial activity toward 4 bacterial strains, including Gram-positive bacteria Staphylococcus aureus (ATCC 43300, ATCC 25923 and ATCC 33591) and Gram-negative bacteria Pseudomonas aeruginosa (ATCC 27853). / Neste trabalho, micropartículas de óxido de zinco (ZnO) com morfologia de estrela foram preparadas à temperatura ambiente por um método novo e simples e decoradas com nanopartículas de ouro (AuNPs) e prata (AgNPs). A presença de tioureia durante a precipitação do ZnO em meio alcalino permitiu o controle do tamanho e forma e a funcionalização da superfície com íons tiocianato (SCN-). Uma série de imagens de MET da amostra preparada em pH 12 sugere que as partículas crescem de acordo com o mecanismo conhecido como “coalescência orientada”. O espectro de emissão destas partículas mostrou uma característica interessante: a posição da banda de emissão pode ser ajustável alterando o comprimento de onda de excitação. AuNPs e AgNPs foram sintetizadas in situ na superfície do ZnO pelo método da fotorredução, sendo que a simples mudança nas proporções ZnO/AgNO3 ou ZnO/HAuCl4 é capaz de controlar os diâmetros médios das partículas. A presença dos íons SCN- na superfície do semicondutor impede o crescimento incontrolável de nanopartículas de Ag em diferentes morfologias e elevados graus de polidispersidade. DRX, MEV, MET, FTIR, UV-vis-NIR e PL foram utilizados para a caracterização da estrutura, morfologia e as propriedades ópticas de nanoestruturas puras e híbridos. Finalmente, as nanoestruturas híbridas ZnO/Ag apresentaram performance superior para aplicações em fotocatálise e atividade bactericida quando comparadas com o ZnO puro. Neste trabalho, foi estudada a fotodegradação de uma solução aquosa de azul de metileno sob irradiação UVA e a atividade bactericida foi testada para 4 estirpes bacterianas, incluindo as bactérias Gram-positivas Staphylococcus aureus (ATCC 43300, ATCC 25923 e ATCC 33591) e Gram-negativas Pseudomonas aeruginosa (ATCC 27853).

O presente trabalho de Doutorado tem como objetivo investigar a influência de materiais lamelares prístinos e modificados e a influência de diferentes rotas sintéticas nas propriedades físico-químicas do amido termoplástico, utilizando glicerol como plastificante. Para tanto, empregou-se para a produção dos materiais híbridos uma argila sintética da família das hectoritas (Laponita RD) na forma prístina e também modificada com íons berberine e carnosina, além de um hidróxido duplo lamelar (HDL) constituído por íons Zn2+/Al3+ intercalado com carboximetilcelulose (CMC). O amido e o material lamelar foram combinados, utilizando as metodologias de casting e extrusão, nas concentrações de 2,5 e 5,0 % (m/m) de argila ou HDL com relação ao polissacarídeo. Já quantidade de plastificante empregada foi variável, dependendo da rota de preparação empregada, sendo de aproximadamente 20 % (m/m) via casting e 30 % (m/m) via extrusão com relação ao amido. Conforme mostram os difratogramas de raios X dos filmes obtidos pelo método casting, todos os filmes contendo argila em sua composição exibem um sinal largo de difração na região de baixo ângulo de 2θ, embora pouco intenso, indica a existência de certa quantidade de nanocompósito do tipo intercalado. Já para os materiais obtidos via extrusão, os sinais de difração em baixo ângulo são consideravelmente alargados e muito pouco intensos. A propriedade térmica do amido termoplástico foi piorada em todos os casos estudados nos materiais contendo argila ou HDL em sua composição. A presença de carga inorgânica na formulação dos materiais híbridos preparados não retardou o processo de decomposição não-oxidativo do amido. A presença de uma maior quantidade de glicerol nos materiais obtidos por extrusão resultou em uma antecipação ainda maior no principal evento de perda de massa, em comparação com os mesmos materiais obtidos via casting. Devido à alta característica hidrofílica do amido, materiais lamelares intercalados com espécies que possuem maior caráter hidrofílico, como a Laponita prístina (contendo apenas íons Na+) e a carnosina mostraram uma melhor dispersão pela matriz polimérica, através da análise por técnicas de microscopia. Adicionalmente, observou-se uma melhor homogeneidade de distribuição da fase lamelar na fase polimérica nos filmes obtidos por casting em comparação com os materiais obtidos por extrusão. Os resultados mecânicos de todos os materiais híbridos analisados mostram tendências pouco conclusivas com relação ao amido termoplástico. Em geral, observa-se uma melhora muito sutil na máxima resistência a tração com a presença de material lamelar na composição dos materiais testados, além de uma diminuição na elongação máxima. Da mesma forma, a permeabilidade a gases dos filmes contendo argila ou HDL em sua composição mostrou resultados pouco conclusivos com relação ao amido termoplástico, geralmente exibindo uma redução modesta na permeabilidade. A investigação do perfil de biodegradação dos materiais contendo fase lamelar em sua composição mostrou que apenas a amostra contendo Laponita modificada com carnosina obtida por extrusão foi capaz de retardar significativamente a conversão do carbono das cadeias poliméricas em CO2, com relação ao amido termoplástico. / This present Thesis aimed to investigate the influence of pristine and modified layered materials and the influence of different preparation routes on the physicochemical properties of thermoplastic starch, using glycerol as plasticizer. To reach this goal, it was used to produce hybrid materials a synthetic clay belonging to the hectorite family (Laponite RD) in both pristine form and modified with berberine and carnosine ions and also a layered double hydroxide (LDH) comprised of Zn2+/Al3+ ions intercalated with carboxymethylcellulose (CMC). Both starch and the layered material were combined using casting and extrusion methodologies, using concentrations of 2.5 and 5.0 % (w/w) of clay or LDH relative to starch. The amount of plasticizer utilized was variable, depending on the preparation route employed. It was used approximately 20 % (w/w) of glycerol on casting route and 30 % (w/w) on extrusion route relative to starch. According to X ray diffractograms of the films obtained by casting route, all hybrid films that contain clay in their composition exhibit a large diffraction signal at low 2θ angle values, albeit its low intensity, indicates the existence of a certain contribuition of a intercalated nanocomposite. On the other hand, the hybrid materials obtained through extrusion method, these low angle diffraction signals are very broad and possess very low intensity. The thermal properties of thermoplastic starch were worsened in all studied cases after combined with clay or LDH. The presence of inorganic filler on the formulation of hybrid materials does not postpone the beginning of the non-oxidative decomposition process of starch. A higher amount of glycerol on the final materials obtained through extrusion resulted in an even greater anticipation on the main mass loss event in comparison to the analogous materials obtained using casting technique. Due to the high hydrophilic nature of starch, layered materials intercalated with ionic species that show higher hydrophilicity such as pristine Laponite (containing solely Na+ ions) and carnosine exhibited better dispersion through the polymer matrix, after being analyzed with microscopic techniques. Additionaly, it was observed a higher homogeneity of distribution of the layered phase over the polymer phase on the films obtained through casting in comparison to the materials obtained through extrusion. The tensile tests of all analyzed hybrid materials show a poorly conclusive trend in comparison to thermoplastic starch. In general, it was observed a subtle improvement on the maximum tensile strength of the materials containing layered material in their composition and also a decrease in the maximum elongation. In a same trend, gas permeability of the films was poorly conclusive in comparison to thermoplastic starch, generally resulting in a subtle reduction of permeability values. The investigation of biodegradation profile of the materials containing inorganic filler show that only Laponite modified with carnosine ions was able to postpone significatively the conversion of carbon from the polymer chains to CO2 in comparison to thermoplastic starch.

Neste trabalho realizou-se a síntese e caracterização de materiais contendo óxidos de lantanóides incorporados em sílica mesoporosa ordenada, os quais foram utilizados como catalisadores no processo de ozonização de compostos orgânicos poluentes. Empregando-se o método de impregnação úmida, realizou-se a incorporação de óxido de cério e óxido de lantânio no suporte mesoporoso, do tipo SBA-15. Utilizaram-se diferentes precursores dos óxidos metálicos, a fim de verificar a influência que a fonte do cátion metálico exerça tanto nas características estruturais, texturais e morfológicas dos materiais quanto na atividade catalítica. A caracterização destes materiais mostrou que em todas as amostras não houve colapso da estrutura ordenada de mesoporos da SBA-15. Porém nos materiais incorporados observou-se a diminuição da área superficial específica e o volume de poro, devido à presença do CeO2 ou do La2O3 tanto na superfície do suporte quanto no interior dos mesoporos. Também foi possível identificar as fases cristalinas destes óxidos após a etapa de incorporação. Os catalisadores foram empregados na degradação de um azocorante, Preto Remazol B. Para todos os materiais verificou-se que a ozonização catalítica heterogênea proporcionou o aumento da mineralização em relação ao processo de ozonólise. Para os catalisadores que continham CeO2, os melhores resultados de mineralização do azocorante foram obtidos para os catalisadores cujos precursores eram complexos metálicos. Para estes materiais obteve-se um incremento de 65% em comparação com a ozonólise, sem que houvesse um grande aumento no consumo de ozônio. Para os materiais que continham La2O3, o catalisador cujo precursor do óxido foi um dos sais inorgânicos utilizados (nitrato de lantânio hidratado) apresentou o melhor teor de mineralização, sendo 72% superior em relação à ozonólise, ao final de 60 minutos. Os catalisadores contendo óxido de cério incorporado à SBA-15 também foram empregados no processo de ozonização catalítica de mais duas espécies orgânicas de grande relevância ambiental: fenol e ácido salicílico. Para o primeiro, houve um incremento mínimo na remoção da matéria orgânica de 70%, para todos os catalisadores testados, em relação à ozonólise, após 60 minutos. Entretanto, apenas dois deles (SBA-Ce(Gly) e SBA-Ce(Cl)) apresentaram um consumo de ozônio semelhante à ozonólise, o que indica que estes eram os mais eficientes. Na degradação do ácido salicílico a sinergia entre o suporte mesoporoso ordenado de elevada área superficial com o óxido de cério mais uma vez mostrou-se eficiente na mineralização da espécie orgânica, sendo obtidos teores de mineralização superiores a 90% para a ozonização catalítica contra 60% para a ozonólise, ao final de 60 minutos de tratamento / The aim of this work was the synthesis and characterization of materials with lanthanide oxides incorporated in ordered mesoporous silica, which were used as catalysts on the ozonation of organic pollutants. The incorporation of cerium and lanthanum oxides on the mesoporous support, SBA-15 type, was made by wet impregnation method. Different metal oxides precursors were used in order to investigate the influence in structural, textural and morphological characteristics of the materials and in catalytic activity. No collapse in the ordered mesopores structure of SBA-15 was observed after lanthanide oxides incorporation. However the hybrid compounds presented lower specific surface area and pore volume. It was observed the presence of CeO2 and La2O3 in the external support surface and in the interior of the mesopores. It was also possible to identify crystalline phases of these oxides after the incorporation step. The catalysts were employed on the degradation of an azo dye, Remazol Black B. For all samples it was found that the heterogeneous catalytic ozonization provided an increase in the mineralization levels of this organic species compared with the results of the ozonolysis. For the CeO2-based materials, the best results were achieved for the catalysts whose precursors were the metal complexes. For these materials the mineralization of the Remazol Black B was, at least, 65% superior to ozonolysis alone, without a great increase in the consumption of ozone. For the La2O3-based materials, the best result was obtained for the catalyst which oxide precursor was one of the inorganic salt (lanthanum nitrate hydrate). The mineralization was 72% higher than the ozonolysis alone after 60 minutes of treatment. The catalysts containing cerium oxide incorporated into the SBA-15 were also employed in the catalytic ozonization of two other organic species of great environmental importance: phenol and salicylic acid. For the first, there was a minimal increase in the removal of the organic matter when compared with ozonolysis alone. However, only two of them (SBA-Ce(Gly) e SBA-Ce(Cl)) showed a consumption of ozone similar to ozonolysis, indicating that these were the most efficient. In salicylic acid degradation, the mineralization achieved was greater than 90% for the catalytic ozonation versus 60% for the ozonolysis alone, after 60 minutes of treatment

De nouveaux précurseurs borates-triéthoxysilanes comprenant le closo-decahydrodecaborate ont été préparés et immobilisés dans la silice. L'introduction des groupements trialkoxysilyles sur les clusters (NH4)2B10H10, a été réalisée par condensations électrophiles faisant appel à des réactifs nucléophiles dans des conditions douces, tout en épargnant l'utilisation d'électrophiles ou de catalyseurs coûteux. Les borates-trialkoxysilanes obtenus ont été caractérisés par RMN 1H, 13C, 11B, 29Si, 31P, IRTF, analyse élémentaire et spectroscopie de masse. Comme preuve de concept, ces précurseurs ont été incorporés de manière covalente dans les pores d'une silice mésoporeuse, SBA-15. Tous les matériaux hybrides mésoporeux et modifiés avec du borate-triéthoxysilane ont été caractérisés par RMN solide 11B et 29Si, DRX, MET, les analyses élémentaires et étude de l'adsorption d'azote (méthode BET). Les précurseurs silylés-borate ont été combinés avec des nanoparticules de silice pour une utilisation éventuelle dans BNCT, où des NPs d'environ 100 nm ont été synthétisées comprenant deux types de centres luminescents différents. FITC silylé (isothiocyanate de fluorescéine) et complexe Eu (III) silylé ont été respectivement immobilisés dans des nanoparticules de silice par le procédé sol-gel. Les deux types de nanoparticules luminescentes ont été fonctionnalisés par les groupes silylés-borates et caractérisés par RMN du solide 11B, 31P et 29Si, DLS, MET, analyses élémentaires, d'adsorption d'azote et spectrophotométrie. / New borate-triethoxysilane precursors comprising the closo-decahydrodecaborate cluster were prepared and immobolized into hybrid silica materials. The synthesis of silylated clusters starting from (NH4)2B10H10 and silane precursors R-Si(OEt)3 through Electrophilic Induced Nucleophilic Reactions was performed under mild conditions, the silylated clusters were analyzed by 1H, 13C, 11B, 29Si, 31P NMR, IR, elemental analyses and mass spectroscopy ES-ESI. As a proof of concept, the borate-triethoxysilane precursors were covalently incorporated into the pores of mesoporous silica, SBA-15 type. All mesoporous materials modified with borate-triethoxysilane were characterized by 11B and 29Si solid state NMR, XRD, TEM, elemental analyses and Nitrogen sorption studies. The silylated-borate precursors were combined with dye-doped silica nanoparticles for possible future use in BNCT technique, where ~100 nm nanoparticles were synthesized comprising two different types of luminescent centers. Silylated FITC (fluorescein isothiocyanate) and silylated Eu(III) complexes were embedded into silica nanoparticles through sol-gel process. Both types of luminescent nanoparticles were functionalized with the silylated-borate clusters and characterized by 11B, 31P and 29Si solid state NMR, DLS, TEM, elemental analyses, Nitrogen sorption studies and spectrophotometer.

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Le travail de recherche de cette thèse consiste en le développement de nouveaux matériaux hybrides organiques-inorganiques pour des applications en nanotechnologie, nanomédicine et diagnostic. Dans ce contexte, des cristaux poreux de zéolite-L ont été utilisé comme nano-vecteur pour faire de la transfection d’ADN et d’ANP, en combinaison avec le relargage de molécules hôtes placées dans les pores. Des nanoparticules de silice mesoporeuses multifonctionnelles ont été utilisées pour traiter le glioblastome, en combinant la thérapie génique avec l’administration durable d’un principe actif. Des nano-coquilles hybrides biodégradables ont été encore développés pour encapsuler des protéines et les relâcher dans les cellules vivantes. Dans le domaine de la détection d’acides nucléiques, des fibres optiques à cristal photonique, fonctionnalisées avec des sondes d’ANP, ont été exploitées comme plateformes optiques pour faire de la détection ultra-sensible d’oligonucléotides ou d’ADN génomique. Enfin, la squelette de l’ANP a été modifié à créer des sondes fluorescentes pour reconnaître et détecter la présence des séquences cibles spécifiques. / The research work presented throughout this thesis focuses on the development of novel organic-inorganichybrid materials for applications in nanotechnology, nanomedicine and diagnostics. In such a context, porous zeolite-L crystals have been used as nanocarriers to deliver either DNA or PNA in live cells, in combination with the release of guest molecules placed into the pores. Multifunctional mesoporous silica nanoparticles have been designed to treat glioblastoma, combining gene therapy with the sustained delivery of a chemotherapy agent. Biodegradable hybrid nano-shells have been furthermore created to encapsulate proteins and release them in living cells upon degradation of the outer structure in reductive environment. In the field of nucleic acid detection, photonic crystal fibers, functionalized with specific PNA probes, have been exploited as optical sensing devices to perform ultra-sensitive detection of DNA oligonucleotides or genomic DNA. Eventually, the PNA backbone has served as scaffold to synthesize fluorescent switching probes able to recognize and to detect the presence of specific target sequences.

Différents systèmes polyoxométallates@M-colorants ont été réalisés dans cette thèse pour électrochimique dégagement d'hydrogène catalytique et génération photocourant.• Des films hybrides, basés sur des interactions électrostatiques entre une porphyrine tetracationique et des nanoparticules stabilisées par des POMs du type POM@Pt sur ITO, ont été formés par la méthode dite couche par couche et ont été utilisés pour la génération de H2 ou de photocourant. • Pour améliorer le transfert de charge entre les nanoparticules POM@M et le substrat, la réduction de l'oxyde de graphène a été réalisée pour former des systèmes hybrides rGO/POM@Pt. Le dégagement d'hydrogène a été mesuré.• Les copolymères polycationiques bis-porphyrine ont également été obtenus par électropolymérisation avec des espaceurs bis-pyridinium. Par réaction de métathèse, l’incorporation avec divers POM de type Keggin ou des nanoparticules du type POM@Ag ont ensuite été realise. Leurs performances photovoltaïques ont ensuite été étudiées.• Enfin des films hybrides PEDOT dopés avec des nanoparticules du type POM@M ont également été fabriqués. Les performances photovoltaïques ont été examinés montrant une forte amélioration sous illumination dans le domaine du visible. L’ensemble de ces matériaux hybrides ont montré des propriétés intéressantes pour des applications photovoltaïques et la conversion d'énergie. / Polyoxometalates@M NPs-dyes molecular hybrid systems were realized in this thesis for electrochemical catalytic hydrogen evolution and photocurrent generation. • First, hybrid films, based on electrostatic interactions between the tetracationic porphyrin and POMs@Pt NPs composites on ITO slides, were formed by the so called Layer-by-Layer method for HER and photocurrent generation.• To improve the charge transfer between POMs@M NPs and the substrate, reduced graphene oxide was introduced to form rGO/POMs@Pt NPs hybrid systems. Hydrogen evolution was measured after dropping this composites onto the surface of glassy carbon electrodes.• Polycationic bis-porphyrin copolymers have been also obtained by an electropolymerization leading to the formation of new bis-porphyrin copolymers with pyridinium as spacers. Incorporation with various Keggin type POMs or POMs@Ag was then achieved, their photovoltaic performances were also studied.• POMs@M NPs doped PEDOT hybrids films have been also fabricated. The photovoltaic performances has been examined showing particularly strong enhancement under visible light. In conclusion, these polyoxometalates based hybrids materials have shown interesting properties for photovoltaic application and energy conversion.