Orientador: Nilson Cristino da Cruz / Banca: Antônio Riul Júnior / Banca: Rogério Pinto Mota / O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp / Resumo: A modificação da tensão superficial de um líquido depositado sobre uma superfície sólida pela aplicação de um campo elétrico entre estes dois elementos é denominada eletromolhabilidade. Neste trabalho foi avaliada a eletromolhabilidade em filmes poliméricos depositados sobre amostras de alumínio pela técnica de Implantação Iônica e Deposição por Imersão em Plasma, IIDIP, usando descargas produzidas a partir de misturas de acetileno ('C IND. 2 'H IND.2') e argônio. Imediatamente após as deposições, os filmes foram expostos a plasmas de 'SF IND. 6' para a obtenção de superfícies mais hidrofóbicas. Em uma primeira etapa do estudo foi variada a condição de deposição, enquanto em etapas posteriores foram variados o tempo e a potência do tratamento com 'SF IND. 6'. A composição dos filmes e a estrutura química foram analisadas por espectroscopias de fotoelétrons de raios X e de absorção no infravermelho. A energia livre de superfície e a molhabilidade foram obtidas através de medidas de ângulo de contato, usando água e diiodometano como líquidos de teste. O fenômeno da eletromolhabilidade foi avaliado medindo-se o ângulo de contato em função da diferença de potencial aplicada entre um fio de cobre em contato com uma gota de água colocada sobre o filme e o substrato de alumínio. A resistividade elétrica superficial foi medida por um eletrômetro digital usando o método das duas pontas. Foi observado que as propriedades dos filmes são fortemente dependentes das condições de deposição e tratamento. Variações tão grandes do ângulo de contato quanto 45° foram obtidas com aplicação de 110 V. / Abstract: The modification of the superficial tension of a liquid deposited onto a solid surface by the application of an electric field between these two elements is denominated electrowetting. In this work it has been evaluated the electrowetting ability of thin polymeric films. The films were deposited onto aluminum plates by plasma immersion ion implantation and deposition technique, PIIID, from acetylene ('C IND. 2 'H IND.2') and argon atmospheres. Immediately after the depositions the films were exposed to 'SF IND. 6' plasmas to enhance the hydrophobicity of the surfaces. A set of samples were produced under different deposition parameters and a second set of experiments were performed submitting the samples to 'SF IND. 6' plasmas under different excitation power and exposure times. The composition of the films has been analyzed by xray photoelectron and Fourier transform infrared spectroscopies. Surface free energy and wettability have been evaluated by contact angle measurements using water and diiodomethane as probe liquids. The electrowetting effect was quantified by measuring the contact angle as a function of the DC voltage applied between a copper wire in contact with the water droplet placed onto the film and the aluminum substrate. Surface electrical resistivity was measured by a digital electrometer using the two-point probe method. It has been observed that film properties are strongly dependent on both the conditions of deposition and treatment. Variation as high as 45° in the contact angle have been observed with the application of 110 V. / Mestre

A new approach to the fabrication of polymeric thin films is presented. This approach, chemical vapor copolymerization (CVcP), has all the advantages of chemical vapor polymerization (CVP), including exceptional purity, highly conformal coatings, continuous films even when very thin, low stress, and low environmental impact. The range of film properties available by CVcP is much greater than by CVP. A specially modified deposition system was constructed to study deposition kinetics. A model was developed which allowed quantification of the order of initiation of paraxylylene (PX), which is the initiation system for all the work reported here. This model suggests a trimer diradical is the smallest stable diradical species formed by PX at room temperature, confirming thermodynamic predictions. This system also allows the calculation of reactivity ratios of PX with vinylic comonomers. A model is developed in which reactivity ratios can be determined if the following quantities are known: a) thickness vs. position of the final film; b) partial pressures of each reactive species entering the deposition chamber and c) composition vs. position in the final film. This model was tested yielded reasonable values for reactivity ratios. A polymeric film extremely low in refractive index (1.38-1.39 in the visible region) is presented. This film is formed by copolymerizing poly(parachloroxylylene), or PX-C, with perfluorooctyl methacrylate (PFOMA). The refractive index of the homopolymers, by contrast, are in the 1.60-1.68 range. Film growth rates are very low for this new material. Finally, a new deposition procedure is introduced in which a comonomer with a low vapor pressure is codeposited with PX. The reactor temperature is above the ceiling temperature of PX deposition, but at a temperature where the comonomer can condense. This makes the deposition environment extremely rich in comonomer, yielding films whose final properties are nearly identical to films composed entirely of the comonomer. The procedure is demonstrated using n-phenyl maleimide (NPMI) as a comonomer; films produced had thermal stabilities nearly matching those of poly(NPMI). This procedure has great promise for broadening the use of polymeric thin films in the microelectronics industry, as well as other fields. / Ph. D.

Made available in DSpace on 2014-06-11T19:23:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-29Bitstream added on 2014-06-13T19:09:11Z : No. of bitstreams: 1 rangel_rcc_me_bauru.pdf: 2357895 bytes, checksum: 465275c558853ac0d0d40c5775317d62 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A modificação da tensão superficial de um líquido depositado sobre uma superfície sólida pela aplicação de um campo elétrico entre estes dois elementos é denominada eletromolhabilidade. Neste trabalho foi avaliada a eletromolhabilidade em filmes poliméricos depositados sobre amostras de alumínio pela técnica de Implantação Iônica e Deposição por Imersão em Plasma, IIDIP, usando descargas produzidas a partir de misturas de acetileno ('C IND. 2 'H IND.2') e argônio. Imediatamente após as deposições, os filmes foram expostos a plasmas de 'SF IND. 6' para a obtenção de superfícies mais hidrofóbicas. Em uma primeira etapa do estudo foi variada a condição de deposição, enquanto em etapas posteriores foram variados o tempo e a potência do tratamento com 'SF IND. 6'. A composição dos filmes e a estrutura química foram analisadas por espectroscopias de fotoelétrons de raios X e de absorção no infravermelho. A energia livre de superfície e a molhabilidade foram obtidas através de medidas de ângulo de contato, usando água e diiodometano como líquidos de teste. O fenômeno da eletromolhabilidade foi avaliado medindo-se o ângulo de contato em função da diferença de potencial aplicada entre um fio de cobre em contato com uma gota de água colocada sobre o filme e o substrato de alumínio. A resistividade elétrica superficial foi medida por um eletrômetro digital usando o método das duas pontas. Foi observado que as propriedades dos filmes são fortemente dependentes das condições de deposição e tratamento. Variações tão grandes do ângulo de contato quanto 45° foram obtidas com aplicação de 110 V. / The modification of the superficial tension of a liquid deposited onto a solid surface by the application of an electric field between these two elements is denominated electrowetting. In this work it has been evaluated the electrowetting ability of thin polymeric films. The films were deposited onto aluminum plates by plasma immersion ion implantation and deposition technique, PIIID, from acetylene ('C IND. 2 'H IND.2') and argon atmospheres. Immediately after the depositions the films were exposed to 'SF IND. 6' plasmas to enhance the hydrophobicity of the surfaces. A set of samples were produced under different deposition parameters and a second set of experiments were performed submitting the samples to 'SF IND. 6' plasmas under different excitation power and exposure times. The composition of the films has been analyzed by xray photoelectron and Fourier transform infrared spectroscopies. Surface free energy and wettability have been evaluated by contact angle measurements using water and diiodomethane as probe liquids. The electrowetting effect was quantified by measuring the contact angle as a function of the DC voltage applied between a copper wire in contact with the water droplet placed onto the film and the aluminum substrate. Surface electrical resistivity was measured by a digital electrometer using the two-point probe method. It has been observed that film properties are strongly dependent on both the conditions of deposition and treatment. Variation as high as 45° in the contact angle have been observed with the application of 110 V.

Layer-by-layer deposition techniques were used to fabricate films with second order nonlinear optical (NLO) properties. These materials are key to the development of electro-optic modulators used in fiber optic communication systems. Performance benefits and lower manufacturing costs are driving the development of organic NLO materials as replacements for inorganic crystalline materials such as lithium niobate. The layer-by-layer deposition technique in which polyelectrolytes are deposited on a surface by electrostatic effects is called the Ionically Self-Assembled Monolayer or ISAM method. The role of the optically inactive polycation's structure on deposition and chromophore orientation was studied by fabricating films with several different polycations. While the specific interactions responsible for chromophore orientation in ISAM films remains unclear, hydrogen bonding and electrostatic effects are ruled out as the sole sources of orientation. The highest values of χ(2) were observed under pH conditions that resulted in flat and thin layers. The relationship between pH and the optical homogeneity of the film was also explored. Deposition of polymers under pH conditions in which the polymer chains were aggregated in solution results in films that are not suitable for use in devices. In this work, a new layer-by-layer deposition technique was developed. Coined hybrid deposition, it relies on covalent bonds and electrostatic interactions for film fabrication. Optically inactive polyamines were used as sources of positive charges and as binding sites with optically active low molecular weight chromophores functionalized with a reactive triazine ring and negative charged sulfonate groups. Polar ordering of the chromophores was obtained when the deposition was done under conditions in which covalent bonding was the preferred attachment mechanism for the chromophore molecules. pH conditions in which electrostatic attachment dominated resulted in poorer orientation. The effect of adding ionic salts to the dye solutions was studied, with hopes of increasing the chromophore density in the film by shielding inter-dye electrostatic repulsions. A linear relationship in deposited amount, as characterized by absorbance/bilayer, was observed as the salt concentration was increased. Little effect on χ;(2) was observed for films made with the as-received Procion Red MX-5B chromophore. However, films fabricated from purified Procion Brown MX-GRN showed a definite dependence on added salt. Exceptional χ(2) values were obtained for Procion Brown films deposited using 0.5 M NaCl and PAH. The importance of depositing from non-aggregated solutions was again highlighted, as films made with the less soluble Procion Orange were significantly less homogeneous than those made from Procion Red and Procion Brown which were highly soluble. The role of polycation structure on the deposition and orientation of Procion Brown and Red was examined. / Ph. D.

Nesse trabalho é apresentado o estudo de redes neurais artificiais (RNAs) como sistemas de aprendizado, simulação e otimização de processos de deposição de filmes finos poliméricos. Duas técnicas de deposição comumente utilizadas para a fabricação de dispositivos eletrônicos e sensores poliméricos foram escolhidas: i) spin coating ou centrifugação e ii) automontagem. Na primeira técnica, a espessura final dos filmes finos obtidos foi a característica avaliada em função da velocidade de rotação, do tempo de rotação e da concentração da solução polimérica. Como material de deposição, utilizou-se a poli(o-metoxianilina) (POMA). Com a segunda técnica analisou-se a influência sobre a espessura, sobre a condutância elétrica e sobre o espectro de absorção, do número de bicamadas, do tempo de exposição dos filmes a uma solução dopante de ácido clorídrico (HCl) e do pH das mesmas. Os poliíons utilizados nessa técnica foram a polianilina (PAni) e o poli(vinil sulfato de sódio) (PVS). Os filmes obtidos pela segunda técnica de deposição constituem uma classe de sensores capazes de detectar e quantificar concentrações baixas de HCl diluído em água. Os treinamentos e simulações com redes neurais artificiais foram realizados apenas para a espessura dos filmes de POMA e a absorção dos filmes de PAni/PVS. Foram construídas redes neurais artificiais do tipo multilayer perceptron (MLP) utilizando o software MATLAB e o componente Neural Networks Toolbox. A reprodutibilidade e o número de neurônios contidos na camada intermediária foram avaliados. Os resultados mostram que as redes neurais artificiais treinadas fornecem boas respostas simuladas interpolando e extrapolando os valores experimentais utilizados. Como conclusão mostra-se que é possível a utilização dessa ferramenta para auxiliar a engenharia de processos, as técnicas e análises de deposições de filmes finos poliméricos. / In this work it is shown a study of artificial neural networks used as learning and simulating systems to optimize polymeric thin films deposition processes. Two common layer deposition techniques to fabricate polymeric electronic devices and polymeric sensors were chosen: i) spin coating and ii) self-assembly. In the first technique the final thickness of obtained thin films was the analyzed characteristic as a function of spin speed, spin time and solution concentration. For the deposited layers we used poly(o-methoxyaniline) (POMA). In the second technique we analyzed the influence of the number of bilayers, the pH of deposition solutions and the dipping time in the final thickness, electrical resistance and UV-Vis absorption spectra. As polyions, we used polyaniline (PAni) and poly(vinyl sodium sulfate) (PVS). These films could be used as a sensor to detect low concentrations of HCl diluted in water. After obtaining the experimental data we constructed artificial neural networks using multilayer perceptrons (MLP) architecture with MATLAB and its component called Neural Networks Toolbox. The number of neurons in the hidden layer and the reproducibility were analyzed. The results show that the trained artificial neural networks used in this work provide good simulation responses interpolating and extrapolating the experimental data. As a conclusion we show that it is possible to utilize this tool to aid the process engineering and the polymeric thin film deposition techniques and analysis

Nesse trabalho é apresentado o estudo de redes neurais artificiais (RNAs) como sistemas de aprendizado, simulação e otimização de processos de deposição de filmes finos poliméricos. Duas técnicas de deposição comumente utilizadas para a fabricação de dispositivos eletrônicos e sensores poliméricos foram escolhidas: i) spin coating ou centrifugação e ii) automontagem. Na primeira técnica, a espessura final dos filmes finos obtidos foi a característica avaliada em função da velocidade de rotação, do tempo de rotação e da concentração da solução polimérica. Como material de deposição, utilizou-se a poli(o-metoxianilina) (POMA). Com a segunda técnica analisou-se a influência sobre a espessura, sobre a condutância elétrica e sobre o espectro de absorção, do número de bicamadas, do tempo de exposição dos filmes a uma solução dopante de ácido clorídrico (HCl) e do pH das mesmas. Os poliíons utilizados nessa técnica foram a polianilina (PAni) e o poli(vinil sulfato de sódio) (PVS). Os filmes obtidos pela segunda técnica de deposição constituem uma classe de sensores capazes de detectar e quantificar concentrações baixas de HCl diluído em água. Os treinamentos e simulações com redes neurais artificiais foram realizados apenas para a espessura dos filmes de POMA e a absorção dos filmes de PAni/PVS. Foram construídas redes neurais artificiais do tipo multilayer perceptron (MLP) utilizando o software MATLAB e o componente Neural Networks Toolbox. A reprodutibilidade e o número de neurônios contidos na camada intermediária foram avaliados. Os resultados mostram que as redes neurais artificiais treinadas fornecem boas respostas simuladas interpolando e extrapolando os valores experimentais utilizados. Como conclusão mostra-se que é possível a utilização dessa ferramenta para auxiliar a engenharia de processos, as técnicas e análises de deposições de filmes finos poliméricos. / In this work it is shown a study of artificial neural networks used as learning and simulating systems to optimize polymeric thin films deposition processes. Two common layer deposition techniques to fabricate polymeric electronic devices and polymeric sensors were chosen: i) spin coating and ii) self-assembly. In the first technique the final thickness of obtained thin films was the analyzed characteristic as a function of spin speed, spin time and solution concentration. For the deposited layers we used poly(o-methoxyaniline) (POMA). In the second technique we analyzed the influence of the number of bilayers, the pH of deposition solutions and the dipping time in the final thickness, electrical resistance and UV-Vis absorption spectra. As polyions, we used polyaniline (PAni) and poly(vinyl sodium sulfate) (PVS). These films could be used as a sensor to detect low concentrations of HCl diluted in water. After obtaining the experimental data we constructed artificial neural networks using multilayer perceptrons (MLP) architecture with MATLAB and its component called Neural Networks Toolbox. The number of neurons in the hidden layer and the reproducibility were analyzed. The results show that the trained artificial neural networks used in this work provide good simulation responses interpolating and extrapolating the experimental data. As a conclusion we show that it is possible to utilize this tool to aid the process engineering and the polymeric thin film deposition techniques and analysis