The goal of the research in this dissertation is to design and characterize embedded passive components, interconnects, and circuits in inhomogeneous, multi-layer liquid crystalline polymer (LCP) substrates. The attenuation properties of inhomogeneous multi-layer LCP substrates were extracted up to 40 GHz. This is the first result for an inhomogeneous LCP stack-up that has been reported. The characterization results show excellent loss characteristics, much better than FR-4-based technology, and they are similar to LTCC and homogeneous LCP-based technology. A two-port characterization method based on measurements of multiple arrays of vias is proposed. The method overcomes the drawbacks of the one-port and other two-port characterizations. Model-to-hardware correlation was verified using multi-layer model in Agilent ADS and measurement-based via model using arrays of the vias. The resulting correlations show that this method can be readily applied to other vertical interconnect structures besides via structures. Comprehensive characterizations have been conducted for the efficient 3D integration of high-Q passives using a balanced LCP substrate. At two different locations from three different large M-LCP panels, 76 inductors and 16 3D capacitors were designed and measured. The parameters for the measurement-based inductor model were extracted from the measured results. The results validate the large panel process of the M-LCP substrate. To reduce the lateral size, multi-layer 3D capacitors were designed. The designed 3D capacitors with inductors can provide optimized solutions for more efficient RF front-end module integration. In addition, the parameters for the measurement-based capacitor model were extracted. Various RF front-end modules have been designed and implemented using high-Q embedded passive components in inhomogeneous multi-layer LCP substrates. A C-band filter using lumped elements has been designed and measured. The lumped baluns were used to design a double balnced-mixer for 5 GHz WLAN application and a doubly double-balanced mixer for 1.78 GHz CDMA receiver miniaturization. Finally, to overcome the limitations of the lumped component circuits, a 30 GHz gap-coupled band-pass filter in inhomogeneous multi-layer LCP substrates, and the measured results using SOLT and TRL calibrations have been compared to the simulation results.

The monomer, p-acryloyloxybenzoic acid (ABA) was synthesized by condensation reaction of acryloyl chloride and p-hydroxybenzoic acid in alkaline medium. Polymerization of the monomer and grafting of the produced polymer (PABA) onto high density polyethylene (HDPE) were expected to be carried simultaneously in melt mixing at high temperature. The graft copolymerization was studied at varying concentrations of the monomer in the reaction mixture at constant temperature (200 0C). Grafted HDPE samples were investigated by several techniques such as DSC, FTIR, MFI and mechanical testing. The tensile tests of PABA-g-HDPE showed an improvement particularly in stress at yield and Young&rsquo / s modulus whereas the strain at break values showed a decrease for all compositions compared to neat HDPE.

The objective of this study is to synthesize nematic-thermotropic liquid crystalline polymers (LCP) and determine their possible application areas. In this context, thirty different LCP&rsquo / s were synthesized and categorized with respect to their fiber formation capacity, melting temperature and mechanical properties. The basic chemical structure of synthesized LCP&rsquo / s were composed of p-acetoxybenzoic acid (p-ABA), m-acetoxybenzoic acid (m-ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA) and isophthalic acid (IPA) and alkyl-diacids monomers. In addition to mentioned monomers, polymers and oligomers were included in the backbone such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) polymers, and polybutylene naphthalate (PBN), polyhexylene naphthalate (PHN) and poly butylene terephthalate (PBT) oligomers that contain different kinds of alkyl-diols. We adjusted the LCP content to have low melting point (180oC-280oC) that is processable with thermoplastics. This was achieved by balancing the amount of linear (para) and angular (meta) groups on the aromatic backbones together with the use of linear hydrocarbon linkages in the random copolymerization (esterification) reaction. LCP species were characterized by the following techniques / Polarized Light Microscopy, Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Analysis (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray Scattering (WAXS, Fiber diffraction), surface free energy, end group analysis (CEG), intrinsic viscosity (IV) and tensile test. According to these analysis LCPs were classified into five main categories / (I) fully aromatics, (II) aromatics+ PET/PEN, (III) aromatics + oligomers (IV) aromatics + short aliphatic diacids, (V) aromatics + long aliphatic diacids. The foremost results of the analysis can be given as below. DSC analysis shows that some LCPs are materials that have stable LC mesogens under polarized light microscopy. In TGA analysis LCPs that have film formation capacity passed the thermal stability test up to 390oC. NMR results proved that predicted structures of LCPs from feed charged to the reactor are correct. In FTIR due to the inclusion of new moieties, several peaks were labeled in the finger-print range that belongs to reactants. In X-ray analysis, LCP24 (containing PET) was found to be more crystalline than LCP25 (containing PEN) which is due to the symmetrical configuration. Block segments were more pronounced in wholly aromatic LCP2 than LCP24 that has flexible spacers. Another important finding is that, as the amount of the charge to the reactor increases CEG value increases and molecular weight of the product decreases. Selected group V species were employed as reinforcing agent and mixed with the thermoplastics / acrylonitrile butadiene styrene (ABS), nylon6 (PA6), polyethylene terephthalate (PET), polypropylene (PP) and appropriate compatibilizers in micro compounder and twin screw extruder. The blends of them were tested in dog-bone and/or fiber form. In general LCPs do not improve the mechanical properties except in composite application with polypropylene. A significant increase in tensile properties is observed by LCP24 and LCP25 usage. Capillary rheometer studies show that the viscosity of ABS decreases with the inclusion PA6 and LCP2 together. In addition to the composite applications, some LCPs are promising with new usage areas. Such as nano fibers with 200nm diameter were obtained from LCP27 by electrospinning method. The high dielectric constant of LCP29 has shown that it may have application areas in capacitors.

Different monomeric diols, with a central rigid FD unit connected with two aliphatic chains of various length, were prepared to react with aromatic mesogenic triad, TOBC. In this manner, thermotropic polyesters with possible low thermal transition temperatures (including Tmand Ti) and high solubility in organic solvent can be generated in view of the non-linear polymeric chain imposed by the rigid, bent FD moieties. In addition to the effect of the aliphatic chain length, polyesters of different molecular weight will be obtained by different synthesis approach (or fractionation of the resulting polyester product) and therefore, the influence of molecular weight on liquid crystalline properties can be evaluated.

No description available.

The pulsed field gradient fourier transform nuclear magnetic resonance (PFG-FTNMR) method to measure translational diffusion coefficients in multicomponent systems has been applied to amphiphilic molecules forming liquid crystalline phases. By analyzing the concentration dependence of the diffusion coefficients of water and amphiphile in a micellar system of N,N-dimethyldodecy lamine oxide (DDAO) in water it was possible to conclude that the micelles formed were polydisperse in size and shape. It was also shown that solubilization of small amounts of hydrophobic molecules into the micelles induces spherical micelles of a narrow size distribution. From the magnitude of the lateral diffusion coefficient in the cubic phase of DDAO/water it was concluded that this phase is built up of bicontinous aggregates. The lipid lateral diffusion in the cubic phase of monooleoylglycerol (MO)/water has been measured. The decrease in the lateral diffusion of MO in this phase, when the water was replaced by glycerol, was ascribed to changes in viscosity in the polar region. Measurements by electron spin resonance and time-resolved fluorescence spectroscopy showed that changes in viscosity of the solvent also affected the motions in the hydrocarbon region. The diffusion coefficients of all three components in the cubic phase located in the lowwater region of the ternary system of diacylglycerol (DAG)/soybean phosphatidylcholine (SPC)/water have been determined. Conclusive evidence was provided for that this cubic phase is built up of reversed micelles containing mainly SPC in a continous matrix of mainly DAG. The effect on the phase properties of DDAO upon incorporation of the peptide gramicidin D has been investigated. It was shown that gramicidin D induces a lamellar phase at all water contents. The change in the order parameter profile of the C-2H bonds in perdeuterated DDAO upon incorporation of gramicidin D is compatible with theoretical calculations for proteins exhibiting a positive hydrophobic mismatch. A method for using the PFG FTNMR technique in measurements of the transmembrane exchange rate of small molecules in vesicular suspensions is discussed and some preliminary data is shown. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 4 uppsatser</p> / digitalisering@umu

Resumo: As hipóteses mais modernas baseiam o processo de envelhecimento cutâneo em duas teorias: o intrínseco (ou cronológico) e o extrínseco (ou fotoenvelhecimento). Tanto no envelhecimento intrínseco como no extrínseco, as principais alterações da pele são caracterizadas por formação de rugas, flacidez e perda da elasticidade. O palmitato de retinol (PR) é um análogo sintético da vitamina A indicado topicamente para prevenir ou retardar algumas mudanças estruturais e funcionais da pele associadas ao processo de envelhecimento cutâneo, porém é um princípio ativo que apresenta estabilidade química limitada frente à umidade, oxigênio, ácidos, metais e exposição à luz. Assim, o objetivo deste trabalho foi desenvolver um sistema líquido-cristalino à base de silicone para a liberação prolongada e maximização da estabilidade do palmitato de retinol. Utilizando-se o método de titulação da fase aquosa, foram construídos dois diagramas ternários de fases, ambos constituídos por Procetyl AWS® (tensoativo) e água e por silicone DC 5330® (fase oleosa no diagrama 1) ou silicone DC 5329® (fase oleosa no diagrama 2). Nos estudos de estabilidade preliminar, as formulações do diagrama 1 (A, B, C e D) e do diagrama 2 (E, F, G e H) foram avaliadas nos seguintes estudos: microscopia de luz polarizada, centrifugação, pH, condutividade eletrolítica, índice de refração e reologia. Dentre estas formulações estudas preliminarmente, a formulação GPR foi selecionada para ser conduzida aos estudos posteriores após a incorporação de 1% do princípio ativo, pois demonstrou a formação de fases líquido-cristalinas evidenciadas sob luz polarizada no microscópio óptico, apresentou-se compatível com o pH fisiológico da pele, apresentou pequeno coeficiente de variação das medidas realizadas referentes aos parâmetros físico- químicos e menor capacidade de desestruturar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Current hypotheses based on the process of skin aging in two theories: the intrinsic (or chronological) and extrinsic (or photoaging). Both in the extrinsic as intrinsic aging, the main skin disorders are characterized by wrinkles, flaccidity and loss of elasticity. Retinyl palmitate (RP) is a synthetic analogue of vitamin A given topically to prevent or delay some structural and functional changes of the skin associated with aging, but is an active principle that has limited chemical stability against moisture, oxygen, acids , metals and exposure to light. Thus, the aim of this study was to develop liquid crystalline system silicon-based for extended release and maximizing the stability of retinyl palmitate in order to optimize the use of topically active principle in the prevention and / or mitigation of aging skin. Using the method of titration of the aqueous phase, was built two ternary phase diagrams, both consist of Procetyl AWS ® (surfactant) and water and silicone DC 5330 ® (oil phase diagram 1) or silicone DC 5329 ® (phase oil in diagram 2). In preliminary studies of stability, the formulations of the diagram 1 (A, B, C and D) and the formulations of the diagram 2 (E, F, G and H) were evaluated in the following studies: polarized light microscopy, centrifugation, pH, electrolitic conductivity, refraction index and rheology. Among these formulations studied preliminarily, the formulation G RP-loaded was selected to be conducted to further studies, since it showed the formation of liquid crystalline phases evidenced by polarized light in an optical microscope, presented consistent with the physiological pH of skin, had a small coefficient of variation of measurements related to the physicochemical and less ability to disrupt the lipid bilayer of the skin due to have a lower concentration of surfactant. The validated analytical methodology for chemical quantification of retinyl... (Complete abstract click electronic access below) / Orientador: Maria Virgínia Costa Scarpa / Coorientador: Marlus Chorilli / Banca: Eneida de Paula / Banca: Sandra Helena Pulcinelli / Mestre

O mecanismo de interferência por RNA (RNAi) é um evento de silenciamento gênico através da degradação do RNA mensageiro. Desta forma, a administração de siRNA (molécula efetora do RNAi) é uma terapia promissora para o tratamento de diversas doenças como o câncer. Porém, para a sua efetiva aplicação terapêutica é necessário o desenvolvimento de sistemas de liberação capazes de liberar o siRNA nas células alvo, promover a sua internalização celular e evitar a sua degradação. Dentre os sistemas de liberação, os de liberação localizada, como os sistemas de geleificação in situ, apresentam vantagens sobre administração sistêmica. Formulações fluidas precursoras (FFP) que formam sistemas líquido cristalinos viscosos in situ podem ser obtidas a partir de lipídeos anfifílicos que absorvem água do meio e se rearranjam. Neste contexto, a presente pesquisa teve como objetivo avaliar o gel formado in situ a partir da FFP (G-FFP), composta por monoglicerídeos (MO), polietilenoimina (PEI), propilenoglicol (PG) e tampão tris, como sistema de liberação localizada de siRNA na terapia do câncer de pele. Os resultados mostraram que o G-FFP é uma mistura de fase cúbica e fase hexagonal. O G-FFP liberou o siRNA de maneira sustentada e complexado ao PEI. A FFP pode ser esterilizada por filtração em membrana e foi capaz de complexar altas concentrações de siRNA (15 mM) e de proteger o siRNA da degradação. A citotoxicidade foi dependente da concentração de FFP e esta quando complexada com siRNA teve a toxicidade diminuída. O siRNA liberado do G-FFP foi internalizado pelas células A431, FaDu, HeLa, A549, WM35/DLC2-GFP e MCF-7/DLC2-GFP. Além disto, siRNAs específicos liberados pelo G-FFP foram capazes de reduzir a expressão da proteína Firefly luciferase em células HeLa e FaDu, pórem não foram capazes de reduzir a expressão do receptor do fator de crescimento epidérmico (EGFR) nas células A431, HeLa, A549 e FaDu. A redução da expressão de EGFR em células A549 foi observado quando a terapia com siRNA foi combinada com internalização fotoquímica. Destes resultados, pode-se inferir que a transfecção celular do siRNA e o silenciamento gênico promovido por ele foi dependente tanto do tipo de linhagem celular como do alvo desejado. Os estudos in vivo mostraram que ocorre a formação de gel intratumoral e após 3 dias da administração intratumoral da FFP contendo siRNA específico para EGFR houve redução de 30% no tamanho dos tumores comparados aos tumores tratados com FFP sem siRNA. Diante destes resultados, pode-se concluir que o sistema desenvolvido tem potencial como sistema de liberação localizada de siRNA quando aplicado subcutaneamente ou intratumoral, uma vez que complexa o siRNA, promove a sua internalização celular e o siRNA liberado no citoplasma das células pode reduzir a expressão de proteínas de interesse. / RNA interference (RNAi) is a mechanism in which small interfering RNA molecules (siRNA) inhibit gene expression, by causing the messenger RNA degradation. Thus, siRNA is a promising therapy for the treatment of several diseases such as cancer. However, the development of delivery systems able to protect the siRNA from degradation and promote its cell uptake is essential for therapeutic use of siRNA. Among the delivery systems, the localized delivery system such as in situ gelling delivery system, have advantages over systemic administration. Precursor fluid formulations (FFP), which forms in situ viscous liquid crystalline systems, can be obtained from amphiphilic lipids that absorb water from the environment and self-assembling. In this context, the present study aimed to evaluate the in situ gel formed from the FFP (G-FFP), composed of monoglycerides (MO), polyethyleneimine (PEI), propylene glycol (PG) and Tris buffer, as localized delivery system for siRNA in skin cancer therapy. The results showed that the G-FFP is a mixture of cubic and hexagonal phase. The G-FFP sustained release of siRNA and the siRNA is released complexed with PEI. The FFP can be sterilized by membrane filtration at 0.22 ?m. FFP was able to complex high siRNA concentration (15 mM) and protect the siRNA from degradation. The cytotoxicity was dependent on the FFP concentration, when FFP was complexed with siRNA it was observed a decreased in toxicity. The siRNA released from G-FFP was uptake by A431, FaDu, HeLa, A549, WM35/DLC2-GFP and MCF-7/DLC2-GFP cells. In addition, specific siRNAs released from G-FFP were able to reduce the expression of Firefly luciferase in HeLa and FaDu cells, but they were unable to reduce the expression of the epidermal growth factor receptor (EGFR) in A431, HeLa, A549 and FaDu cells. The reduction of expression of EGFR in A549 cells was observed when siRNA therapy was combined with photochemical internalization. From these results, can be inferred that the efficiency of siRNA transfection and knockdown was dependent on both the type of cell line and the desired target protein. In vivo studies showed that the gel was formed in situ after intratumoral injection. 3 days after intratumoral administration of FFP containing EGFR specific siRNA, 30% of reduction in the tumors size compared to tumors treated with FFP without siRNA was observed. Based on these results, could be concluded that the developed system is a potential siRNA delivery system when administered subcutaneously and intratumoral, because it was able to complex siRNA, promoted its cell uptake and the siRNA released into the cytoplasm of the cell may reduce the expression of target proteins

No description available.

Thermoplastic composites that have been reinforced by thermotropic liquid crystalline (TLCP) fibrils in the microscale and by nanoparticles in the nanoscale are defined as multi-scale wholly thermoplastic composites (WTCs). Multi-scale WTCs have been proposed as lightweight replacements with high performance for some traditional glass fiber (GF) and carbon fiber (CF) reinforced composites materials in various applications. TLCPs are known for performing mechanical properties similar to those of the lower end of CF but significantly better than those of GF. To enhance the mechanical properties of TLPC reinforced WTCs, carbon nanotubes (CNTs) are considered being used as a secondary enhancement in WTCs. CNTs have gathered significant interest in the last 30 years because of their high aspect ratio, high mechanical properties, and other high-performance properties. The focus of this work is on investigating the processing conditions of generating in situ injection-molded multi-scale WTCs, then extending the technology to dual-extrusion and fused filament fabrication (FFF) and obtain high-performance multi-scale WTC products. This dissertation initially focused on investigating the processing conditions, in particular mixing histories and processing temperature profiles, of generating in situ injection-molded multi-scale WTCs, which consist of a representative TLCP, scCO2 aided exfoliated CNTs, and the thermoplastic matrix polyamide 6 (PA 6). The supercooling behavior of the TLCP and thermal stability of PA 6 are studied by applying the rheological methods of small amplitude oscillatory shear (SAOS). Multiple mixing histories with CNTs and processing temperature profiles are analyzed based on the criterion of maximizing tensile properties of multi-scale WTCs and minimizing thermal degradation of the matrix. Under the optimum processing conditions, the in situ injection-molded multi-scale WTCs exhibit a 26% and 34% tensile modulus and strength enhancement, compared to the in situ injection-molded WTCs with no CNTs. Scanning electron micrograph (SEM) images were used to understand the enhancement. The second part of this work is to extend the scCO2 aided in situ multi-scale WTCs processing technology to dual-extrusion and FFF. Multi-scale WTC filaments, which consists of TLCP, CNTs, and polyamide copolymer (PAc), are generated by dual-extrusion, and 3D printed into rectangular specimens in FFF. The 1 wt% CNTs reinforced multi-scale WTC filaments generated by the means of dual-extrusion exhibit 225% and 80% improvement in tensile modulus and strength, respectively, compared to the WTC filaments with no CNTs. In FFF, 40 wt% TLCP/1 wt% CNT/PAc 3D printed specimens with filament laid in longitudinal direction exhibited excellent tensile modulus and strength of 38.92 GPa and 127.16 MPa, respectively. The well-dispersed exfoliated CNTs show high alignment with TLCP microfibrils in the multi-scale WTC filaments and their laid-down specimens, which causes the significant tensile modulus enhancement. Bridging elements are discovered between TLCP fibrils and PAc matrix to improve interfacial adhesion, which is attributed to the well-dispersed exfoliated CNTs. Finally, the significant improvements in tensile properties attributed to scCO2 aided exfoliated CNTs in WTCs are verified on the multi-scale WTCs based on polypropylene (PP). Moreover, additional tensile properties improvements for exfoliated CNTs reinforced multi-scale WTCs are obtained with the use of maleic anhydride grafted polypropylene (MAPP). With 1 wt% CNTs and 16 wt% MAPP dual reinforcement, 20 wt% TLCP reinforced WTCs based on polypropylene (PP) exhibit 265%, 274%, and 182% improvement in the tensile modulus of the filaments, laid up specimens in the concentric pattern and laid up specimens in ±45° rectilinear pattern, respectively. The dual reinforcement also improves the tensile strength of 20 wt% TLCP reinforced WTC filaments by up to 73%. The high alignment between TLCP fibrils and CNTs are confirmed in the multi-scale WTCs based on PP. Besides the bridging elements attributed to CNTs found in the second part of this work, SEM images show that CNTs are partially trapped in TLCP fibrils. / Doctor of Philosophy / Considering the need for environmentally friendly materials, novel thermoplastic composites with high mechanical performance, lightweight, and potentially high recyclability properties were generated in this work. Two types of thermoplastic matrices, polyamide (PA or nylon) and polypropylene (PP) were reinforced with carbon nanotubes (CNTs) and rigid chain polymers known as thermotropic liquid crystalline polymers (TLCPs). CNTs are known for their high mechanical properties and high aspect ratio, which are helpful to reinforce thermoplastic composite materials. During injection molding and the dual-extrusion processes, TLCPs deform into almost continuous microfibrils and reinforce the thermoplastic matrices. Instead of using traditional glass fibers or carbon fibers to reinforce thermoplastics, TLCP reinforced thermoplastic composites, which are defined as wholly thermoplastic composites (WTCs), can retain their mechanical properties during the recycling process such as in injection molding and have better performance during the lay-down process in fused filament fabrication. The goal of this work was to generate CNTs reinforced WTCs for use in injection molding and fused filament fabrication with high mechanical performance. In the injection molding process for generating CNTs reinforced WTC end-gated plaques, it was determined that the optimum thermal mixing histories for the CNTs could be identified by the inspections of the tensile property measurements and scanning electron microscopy (SEM). With the obtained optimum thermal mixing histories with CNTs, CNTs reinforced WTC filaments were generated by dual extrusion technology and used in fused filament fabrication. With 1 wt% addition of CNTs, the tensile properties of WTCs were significantly enhanced in both the filament materials and the laid-down parts. Especially, the CNT reinforced WTC filaments based on nylon matrices exhibited competitive tensile moduli to long carbon fiber reinforced nylon composite filaments, which was also competitive to the properties of aluminum alloys. In addition, the laid-down parts of CNTs reinforced WTC based on PP presented further tensile strength improvement due to the improved interfacial adhesion between the laid-down filaments and between layers, which was attributed to the addition of maleic anhydride grafted polypropylene.