Polímeros conjugados semicondutores tem atraído grande interesse nas últimas décadas devido às possíveis aplicações como componentes ativos em aplicações optoeletrônicas. A adequação destes semicondutores orgânicos para a fabricação de dispositivos depende do entendimento e controle de propriedades eletrônicas básicas: gap fundamental (Eg) e potencial de ionização (IP). Nesse contexto, estudos teóricos baseados em cálculos de primeiros princípios tem se mostrado muito úteis, uma vez que possibilitam a simulação de processos físicos em condições ideais, onde se pode analisar as propriedades eletrônicas de polímeros desconsiderando efeitos do ambiente ou desordem estrutural. A Teoria do Funcional da Densidade (DFT) tem se tornado o método mais comum para o cálculo da estrutura eletrônica do estado fundamental de uma ampla variedade de materiais orgânicos complexos. Embora cálculos DFT baseados na diferença de energias totais tem sido aplicados com sucesso para estimar IPs de moléculas pequenas, este método falha nas propriedades de sistemas conjugados longos. Realmente, a capacidade preditiva da DFT padrão com respeito as propriedades espectroscópicas é frequentemente limitada, entretanto o tratamento adequado das excitações eletrônicas através de abordagens de muitos corpos é ainda muito difícil para materiais orgânicos complexos. Funcionais híbridos que misturam uma fração () de troca exata (EX) não-local ao correspondente semi-local representam uma boa alternativa, embora a quantidade ideal de EX seja, em geral, dependente do sistema. Neste trabalho, adotamos um esquema não-empírico baseado na aproximação G0W0 para identificar o valor ótimo de para o funcional híbrido PBE no qual a correção de autoenergia para o orbital mais alto ocupado (HOMO) de Kohn-Sham generalisado é minimizado. Estudamos, com base nessa estratégia, a dependência com o comprimento das propriedades eletrônicas básicas em uma família de oligômeros conjugados 1D de trans-poliacetileno (TPA). Nossos cálculos mostram que a fração EX ótima (dependente do tamanho) incorporada ao PBEh reproduz com precisão os IPs experimentais determinados em fase gasosa, / Semiconducting conjugated polymers have attracted considerable interest over the past decades due to the promising applications as active components for optoelectronic applications. The suitability of such organic semiconductors for device fabrication relies on quantitative understanding and control of basic electronic properties: fundamental gap (Eg) and ionization potential (IP). In this context, theoretical studies based on first principles approaches have proven useful, through simulating physical processes in ideal conditions, in which one might analyse the electronic properties of polymers apart from the effects of the surrounding environment or structural disorder. Density Functional Theory (DFT) has become an usual choice for calculating the ground state electronic structure of a wide variety of complex organic materials. Although DFT calculations based on total energy differences have been successfully applied to estimate IPs of small molecules, they fail for properties of long conjugated systems. Indeed, the predictive ability of standard DFT with respect to spectroscopic properties is often limited, however a proper treatment of the electronic excitations through many-body approaches is still very difficult for complex organic materials. Hybrid functionals that mix a fraction (_) of nonlocal exact exchange (EX) with the semilocal counterpart represent a good alternative, although the ideal amount of EX is usually system dependent. In this work, we adopt a non-empirical scheme based on the G0W0 approximation to identify the optimum _ value for the PBE hybrid functional for which the self-energy correction to the generalized Kohn-Sham highest occupied molecular orbital (HOMO) is minimized. Based on this strategy we study the size dependence of the basic electronic properties in a family of 1D _-conjugated oligomers of trans-polyacetylene (TPA). Our calculations demonstrate that the size dependent optimal EX fraction incorporated in PBEh accurately reproduces IPs from experimental gas phase data, although no particular constraint has been imposed a priori. Furthermore, we note that the optimum _-value decreases exponen tially with chain length going from _ w0.85 for the smaller oligomer (ethylene, n=1) up to _ w0.75 extrapolated for an isolated TPA chain. The accuracy of our optimized PBEh in predicting IPs and Eg is superior to other conventional mean field approaches, as demonstrated for a selected set of conjugated molecules such as acenes and phenylenes. As a result, we can obtain good estimations for the energy barriers of electron transfer in organic/organic interfaces. On the other extreme, we analyse the influence of exact exchange on the electronic structure of the prototypical metal system gold (Au), commonly used as electrode in organic devices. In this case, we confirm the expected result that the insertion of even a small fraction of EX into PBE functional distorts the Au band structure, worsening the description of electronic properties compared to regular PBE. We then proceed to analyse the factibility of studying polymer/metal interface systems using pure DFT. Our calculations reveal that the result is too system-dependent: for the TPA/Au(111) interface, an artificial charge transfer takes place at interface due to an underestimation of the IPs of the conjugated system inherent to the underlying DFT approximation. Finally, our study emphasizes the importance of a physically motivated choice of EX fraction in hybrid functionals for accurately predicting both ionization potentials and fundamental gaps of organic semiconductors relevant for nanoelectronics.

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Magister Scientiae (Medical Bioscience) - MSc(MBS) / Conjugated linoleic acids (CLA) are geometrical and positional isomers of n-6 octadecadenoic acid (linoleic acid, LA, 18:2n-6), which form part of a family of essential polyunsaturated fatty acids (PUFA). There are 28 identified CLA isomers that mostly found in the meat and milk from ruminant animals. CLA has shown to possess a number of health benefits including; reduction in body fat and increased lean body mass, prevention of atherosclerosis, hypertension, increased immune function and in particular the prevention of cancer. The effects of CLA on cancer cell lines will be evaluated to discover the mechanisms that are employed to achieve this great phenomenon on cell growth. The aim of this study was to determine the effect of CLA on various parameters that are essential in the development of cancer cell phenotype. The objectives were to evaluate the effect of CLA on iron-induced lipid peroxidation of microsomes isolated from rat liver cells and in vitro cytotoxicity, cell proliferation and apoptosis in HepG2 hepatocarcinoma cells. The Fatty acid incorporation in HepG2 cells was also assessed.

Conjugated polymers (CPs) are intrinsically fluorescent materials that have been used for various biological applications including imaging, sensing, and delivery of biologically active substances. The synthetic control over flexibility and biodegradability of these materials aids the understanding of the structure-function relationships among the photophysical properties, the self-assembly behaviors of the corresponding conjugated polymer nanoparticles (CPNs), and the cellular behaviors of CPNs, such as toxicity, cellular uptake mechanisms, and sub-cellular localization patterns. Synthetic approaches towards two classes of flexible CPs with well-preserved fluorescent properties are described. The synthesis of flexible poly(p-phenylenebutadiynylene)s (PPBs) uses competing Sonogashira and Glaser coupling reactions and the differences in monomer reactivity to incorporate a small amount (~10%) of flexible, non-conjugated linkers into the backbone. The reaction conditions provide limited control over the proportion of flexible monomer incorporation. Improved synthetic control was achieved in a series of flexible poly(p-phenyleneethynylene)s (PPEs) using modified Sonogashira conditions. In addition to controlling the degree of flexibility, the linker provides disruption of backbone conjugation that offers control of the length of conjugated segments within the polymer chain. Therefore, such control also results in the modulation of the photophysical properties of the materials. CPNs fabricated from flexible PPBs are non-toxic to cells, and exhibit subcellular localization patterns clearly different from those observed with non-flexible PPE CPNs. The subcellular localization patterns of the flexible PPEs have not yet been determined, due to the toxicity of the materials, most likely related to the side-chain structure used in this series. The study of the effect of CP flexibility on self-assembly reorganization upon polyanion complexation is presented. Owing to its high rigidity and hydrophobicity, the PPB backbone undergoes reorganization more readily than PPE. The effects are enhanced in the presence of the flexible linker, which enables more efficient π-π stacking of the aromatic backbone segments. Flexibility has minimal effects on the self-assembly of PPEs. Understanding the role of flexibility on the biophysical behaviors of CPNs is key to the successful development of novel efficient fluorescent therapeutic delivery vehicles.

In this dissertation, three aspects about surface and interface engineering of conjugated polymers and nanomaterials will be discussed. (i) There is a significant promise for electroactive conjugated polymers (ECPs) in applications of electrochemical devices including energy harvesting, electrochromic displays, etc. Among these, ECPs has also been developed as electroactive materials in electrochemical supercapacitors (ESCs). Compared with metal oxides, ECPs are attractive because they have good intrinsic conductivity, low band-gaps, relatively fast doping-and-undoping process, the ease of synthesis, and tunable electronic and structural properties through structural modifications. Here, Multiple-branch-chain 3,4-ethylenedioxythiophene (EDOT) derivatives was designed as crosslinkers in the co-electropolymerization of EDOT to optimize its morphology and improve the cycling stability of PEDOT in the supercapacitor applications. High-surface-area π-conjugated polymeric networks can be synthesized via the electrochemical copolymerization of the 2D (trivalent) motifs benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (BTT) and tris-EDOT-benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (TEBTT) with EDOT. Of all the material systems studied, P(TEBTT/EDOT)-based frameworks achieved the highest areal capacitance with values as high as 443.8 mF cm-2 (at 1 mA cm-2), higher than those achieved by the respective homopolymers (PTEBTT and PEDOT) in the same experimental conditions of electrodeposition (PTEBTT: 271.1 mF cm-2 (at 1 mA cm-2); PEDOT: 12.1 mF cm-2 (at 1 mA cm-2). (ii) In electrochemical process, the suitable choice of appropriate electrolytes to enlarge the safe working potential window with electrolyte stability is well known to improve ECPs’ performance in ESCs applications. Ionic liquids (ILs) are ion-composed salts and usually fluid within a wide temperature range with low melting points. There are many unique characteristics for these intrinsic ion conductors, including high ionic conductivity, wide electrochemical voltage windows in neutral conditions, fast ion mobility in redox reaction process (>10-14 m2 V-1 s-1), low vapor pressure, and environmental stability. These properties qualified ambient-temperature ILs to be applied as supporting medium for various devices and materials processing applications in both industry and academia, overcoming the limitation of volatile organic compounds (VOCs). Especially, ILs have been utilized as superior medium to electrodeposit metals, alloys, semiconductors and ECPs in the application of supercapacitors. Electropolymerization of EDOT and its derivative 4,4'-dimethoxy-3,3'-bithiophene (BEDOT) have been studied in three kinds of imidazolium-based ionic liquids and conducting salt in VOCs with different anions both as the growth medium and the supporting electrolyte, to assess the influence of these anions on their morphology and electrochemical activity. It is found these thiophene polymers grown in ILs with higher viscosity and lower diffusion shows much slower growth rate and orderly morphologies than in Tetrabutylammonium hexafluorophosphate (TBAPF6) dissolved in acetonitrile (ACN), and gives better electrochemical performance via cyclic voltammetry (CV) and galvanostatic charge-and-discharge (CD) studies. Polymers displayed multiple redox peaks in several cases, the possible reasons and origins are discussed. The synthesized polymer can be affected greatly by both the ILs with different anion/cation, and its mutal interation with targeted monomer.. As far as known, there is no systematic study on how the anions of ILs and common organic solution could play a role as a medium both for polymerization and post-polymerization electrolyte for PEDOT and its derivatives. This study can be used as an easy reference and provide experimental diagnositc data when selecting ionic liquids to investigate and optimize thiophene-based electrochemical systems, such as batteries and supercapactiors. (iii) Another aspect about interface chemistry of direct functionalization of nanodiamond with maleimide has also been addressed. Functional nanodiamonds are promising candidates for extensive practical applications in surface science, photonics and nanomedicine. Here, a protocol of direct functionalization is described by which maleimide-derivatized substituents can be appended to the outer shell of thermally annealed nanodiamonds through Diels-Alder reaction. This protocol can be carried out in room temperature, ambient atmosphere, without catalyst, and provide functionalized nanodiamonds with good solubility in organic solution. Also, this method can be applied for other maleimide derivatives,e.g.m aleimide-fluorescene, which can be applied in fluorescence labeling, sensing, and drug delivery. A series of techniques, especially Fourier transform infrared spectroscopy (FTIR), and Solid State Nuclear Magnetic Resonance (SS-NMR) was conducted for the analysis of surface chemistry and the investigation of the two-point binding strategy in details.

This work deals with the optimization of the method for determination of conjugated linoleic acid (CLA) using gas chromatography. The summary about formation and occurrence of CLA in animal materials, its biological effects in human organism and methods suitable for its determination is introduced in the theoretical part of this study. The experimental part verify, if the gas chromatography is applicable method for assesment of CLA in selected biological matrices. The chosen method was introduced and verified at FCH of Brno university of technology. At the end the applicability of this method to CLA determination is discussed here.

Orientador: Deuber Lincon da Silva Agostini / Resumo: Neste trabalho foram produzidas nanofibras eletrofiadas constituídas de poli(álcool vinílico) (PVA) com poli(3,4-etilenodioxitiofeno):poli(estireno sulfonado) (PEDOT:PSS) (PVA/PEDOT:PSS) e nanofibras de poli(álcool vinílico) (PVA) com polipirrol (PPy) (PVA/PPy) com propriedades elétricas para utilização como sensores de gás. O PVA é um polímero isolante, solúvel em água com elevado peso molecular que lhe confere as características ideais para a produção de nanofibras, sendo este usado como polímero de suporte para os polímeros condutores PEDOT:PSS e PPy. Foram investigados o efeito das diferentes concentrações de PVA na produção das nanofibras eletrofiadas, onde a concentração de 6% apresentou os melhores resultados na formação de nanofibras. Também foram investigados a influência das concentrações de PEDOT:PSS e PPy na estrutura e propriedades das nanofibras eletrofiadas, através da análise morfológica e resistividade elétrica, no qual obteve-se a formação de nanofibras para todas as concentrações. Em seguida as nanofibras foram depositadas em eletrodos interdigitados para a realização das caracterizações elétricas e teste como sensor de gás, no qual comprovou-se a sensibilidade das nanofibras constituídas de condutor/isolante na presença de gás amônia (NH3). / Abstract: In this work were produced electrospunnanofibers of polyvinyl alcohol (PVA) with poly(3,4-ethylenedioxythiophene):poly(sulfonated styrene) (PEDOT:PSS) (PVA/PEDOT:PSS) and poly(vinyl alcohol) nanofibers (PVA) with polypyrrole (PPy) (PVA/PPy) with electrical properties for use as gas sensors. PVA is a high molecular weight water soluble insulating polymer which gives it the ideal characteristics for the production of nanofiber, which is used as a support polymer for the PEDOT:PSS and PPy conductive polymers. It wasinvestigated the effect of different PVA concentrations on the production of electrospunnanofibers, where the 6% concentration showed the best results in the formation of nanofibers. The influence of PEDOT:PSS and PPy concentrations on the structure and properties of nanofibers was also investigated, through morphological analysis and electrical resistivity, which obtained the formation of nanofibers for all concentrations. Then the nanofibers were deposited on interdigitated electrodes to perform the electrical characterization and test as a gas sensor, which proved the sensitivity of conductor / insulating nanofibers in the presence of ammonia gas (NH3). / Mestre

This Thesis is devoted to synthesis and characterization of conjugated polymers of three types: (i) copolymers of fluorene-based units with comonomers derived from benzene, anthracene and diphenyloxadiazole; (ii) copolymers combining new thiophene monomers carrying oxadiazole and triazole moieties with various comonomers. Copolymers are designed with the respect to the tuning the optical properties and an improvement in charge transport properties; (iii) polythiophene based polyelectrolytes of two types and the basic characterization of selected physical and optical properties is reported as well as a study of interactions with noble metal nanoparticles. An incorporation of oxadiazole side groups into the fluorene copolymers was followed by the substantial increase in the stability of emission (photoluminescence). Another increase in the emission stability was achieved by the substitution of alkyl side groups on fluorene for the aryl counterparts. Such a change resulted in almost complete suppression of the undesired green emission. Further method was the incorporation of anthracene monomeric units into the main chains which resulted in the best stabilization of emission. An experiment was also made in order to shed some light on the explanation of the mechanism of emission stabilization caused by...

Polymeric membranes typically possess a broad pore-size distribution that leads to much lower selectivity in molecular and ionic separation when compared to membranes made of crystalline porous materials; however, they are highly desirable because of their easy processability and low cost. Recently, a novel type of conjugated microporous polymers (CMPs) has shown uniform pore size and high porosity. However, their brittleness nature has prevented them from preparing robust membranes and using in pressure-driven membrane processes. In this dissertation, we demonstrate the fabrication of robust polycarbazole-type conjugated microporous polymer membranes using an easy to scale-up electropolymerization strategy. The mechanical properties of the CMP membranes were greatly enhanced based on membrane structure optimization and molecular design. The prepared membranes exhibited high uniform sub-nanometer pores and a precisely tunable membrane thickness and properties, yielding high molecular/ionic sieving performance. In addition, using the co-electropolymerization method, the CMP membranes achieve dual softness and functionalization adjustments. The membrane structure comprises rigid monomers to inherit the structural uniformity and flexible and charged monomers to enhance mechanical flexibility and improve ion selectivity by combining the precise size sieving and the Donnan effect. The dual-adjustments result in the further enhancement of the CMP membranes in ionic sieving performance. Inspired by light-gated ion channels in living cells, we further develop a smart artificial light-gated ion channel membrane. The prepared CMP membranes, based on a conjugated microporous polymer (CMP) functionalized with azobenzene and precisely designed on the molecular level, show uniform pore channels and highly sensitive light-switchable response. The photoisomerization results in reversible geometric changes in pore channel size, leading to “on-off-on” light-control over the channels, which results in light-gated ion transport across the smart membrane. The softness adjustment, functionalization adjustment to CMP membranes, and the design of smart CMP membranes provide potential applications for this important category of polymer materials in the membrane field.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18292号 / 工博第3884号 / 新制||工||1596(附属図書館) / 31150 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 中條 善樹, 教授 澤本 光男, 教授 杉野目 道紀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM