The synthesis of mesoporous silica thin films using surfactant templating typically leads to an inaccessible pore orientation, making these films not suitable for membrane applications. Recent advances in thin film synthesis provide for the alignment of hexagonal pores in a direction orthogonal to the surface when templated on chemically neutral surfaces. In this work, orthogonal thin film silica membranes are synthesized on alumina supports using block copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123) as the template. The orthogonal pore structure is achieved by sandwiching membranes between two chemically neutral surfaces, resulting in 90 nm thick films. Solvent flux of ethanol through the membrane demonstrates pore accessibility and suggests a silica pore size of approximately 10 nm. The permeability of ions and fluorescently tagged solutes (ranging from 4,000 to 70,000 Da) is used to demonstrate the membrane’s size selectivity characteristics. A size cut off occurs at 69,000 Da for the model protein BSA. By functionalizing the silica surface with a long chained alkyl group using n-decyltriethoxysilane (D-TEOS), the transport properties of the membranes can be altered. Contact angle measurements and FTIR results show the surface to be very hydrophobic after functionalization. Solvent flux of ethanol through the silica thin film membrane is similar before and after functionalization, but water flux decreases. Thin film silica membranes show much promise for applications in catalysis, bio-sensing, and affinity separations.

Dissolved and Colloidal substances (DisCo) and metals are released from wood during thermomechanical pulp (TMP) production. The mechanical treatment causes that these components have a tendency to accumulate in process waters, as the water circulation systems in integrated paper mills are being closed. Disturbances such as pitch depositions on the paper machine (pitch problems), specks in the paper, decreased wet and dry strength, interference with cationic process chemicals, and impaired sheet brightness and friction properties appear in the presence of DisCo substances. The presence of transition metal ions such as manganese results in higher consumption of bleaching chemicals (hydrogen peroxide) and lowers the optical quality of the final product, and addition of complexing agents, such as EDTA or DTPA, to prevent this is needed. The never ending trends to decrease water consumption and increase process efficiency in pulp and paper production stress that it is very important both to know the effects of wood substances on pulping and papermaking and to be able to remove them in an efficient way. Carried out investigations presented in this thesis show that the lipophilic extractives can be removed from TMP press water to high extent. A 90% decrease in turbidity and a 91% removal of lipophilic extractives from TMP press water can be obtained by addition of a cationic surfactant as foaming agent during flotation. Additionally, fibres located in TMP press water are not removed with the foam fraction but purified. A retained concentration of hydrophilic extractives in the process water indicates that the flotation is selective. Moreover, by introduction of a new recoverable surface active complexing agent, a chelating surfactant, manganese ions in the form of chelates can be successfully removed from the pulp fibres and separated from the process water in the same flotation process. iii The findings presented above indicate new possibilities for internal water cleaning and decreased emissions to water if flotation technology is applied in an integrated mechanical pulp mill. / ReGain/FORE

Šio darbo tikslas - ištirti polioksietilen(20) sorbitano monolaurato, sorbitano monopalmitato, polioksietilen(20) sorbitano tristearato ir sorbitano trioleato įtaką alkilakrilato krospolimero tiesioginės (a/v) emulsijos stabilumui. Tyrimo objektai - emulsija, pagaminta naudojant 0,6% koncentracijos alkilakrilato krospolimerą; nejonogeninės paviršinio aktyvumo medžiagos: polioksietilen(20) sorbitano monolauratas (Tween 20), sorbitano monopalmitatas (Span 40), polioksietile(20) tristearatas (Tween 65) ir sorbitano trioleatas (Span 85). Tyrimo uždaviniai: išanalizuoti literatūros duomenis apie nejonogenines paviršinio aktyvumo medžiagas ir jų įtaką alkilakrilato krospolimero emulsinėms savybėms; ištirti paviršinio aktyvumo medžiagų: polioksietilen(20) sorbitano monolaurato, sorbitano monopalmitato, polioksietilen(20) sorbitano tristearato ir sorbitano trioleato įtaką emulsinių lašelių dydžiui ir klampai; įvertinti paviršinio aktyvumo medžiagų įtaką emulsijos fiziniam stabilumui taikant diferencinio centrifugavimo testą ir šaldymo - šildymo ciklą; įvertinti laikymo sąlygų įtaką emulsinių lašelių dydžiui ir stabilumui. Literatūros analizė parodė, kad net maža alkilkrospolimero koncentracija (0,2-0,8%) pasižymi geromis emulsinėmis savybėmis ją derinant su nejonogeninėmis PAM. Rasta duomenų apie šio polimero sąveiką su polioksietilen(20) sorbitano trioleatu (Tween 85), tačiau šiame darbe tyrinėjami objektai iki šiol nebuvo tyrinėti, todėl yra aktualu ištirti nejonogeninių PAM... [toliau žr. visą tekstą] / Thesis goal - to explore impact of polyethylene glycol sorbitan monolaurate, sorbitan monopalmitate, polyethylene sorbitan tristearate and sorbitan trioleate to stability of direct (oil/water) emulsion of alkyl acrylate crosspolymer. Thesis object – emulsion, made with 0,6% concentration of Alkyl Crosspolymer; non-ionogenic surfactants: polyoxyethylene (20) sorbitan monolaurate, sorbitan monopalmitate, polyoxyethylene (20) sorbitan tristearate, sorbitan trioleate. Thesis objectives – To analyse sources of literary about the effects of non-iogenic surfactants on the stability of emulsion with alkyl acrylate crosspolymer; influence of non-ionogenic surfactants to size of emulsion droplets and viscosity; influence of non-ionogenic surfactants to physical stability of emulsion during centrifugation test and heating-cooling cycle; influence of conditional atmosphere to size of emulsion droplets and stability. The analysis of literary sources revealed that even a small concentration of Alkyl Crosspolymer (0.2–0.8%) has good emulsion properties, when combined with non-ionogenic surfactants. Data on the interaction of this polymer with polyoxyethylene (20) sorbitan trioleate (Tween 85) has been found; however, objects studied in this thesis have not been explored before, thus it is relevant to analyze the effects of non-iogenic surfactants on the stability of emulsion with alkyl acrylate crosspolymer. The obtained results showed that the analyzed non-ionogenic surfactants influence... [to full text]

Abstract Peptide surfactants developed in the Centre for Biomolecular Engineering at The University of Queensland are engineered to combine the advantages of traditional surfactants with biodegradability, biocompatibility, formation of a mechanically strong interfacial cohesive network, and reversible stimuli-responsiveness. In this project, the potential of peptide-stabilised emulsions as delivery systems for small interfering RNA (siRNA) was explored. In recent years, the potential of siRNA as a new class of therapeutics has attracted great attention. The ubiquitous nature of RNA interference (RNAi) implies that siRNA can be used to silence any disease-causing gene to treat any disease. The hurdle that needs to be overcome to turn siRNA therapy into clinical reality is its delivery into the cytosol, where gene silencing by siRNA occurs. Although numerous systems have been developed for the delivery of siRNA, safety and efficiency are major concerns associated with current formulations. Therefore this project aimed to prepare a stable peptide emulsion formulation and to conduct initial tests of its ability to deliver siRNA in vitro. The human tumour suppressor gene p53 and the human breast cancer MCF-7 cell line were used as the model gene and model cell line, respectively. The commercially available lipid-based transfection reagent Lipofectamine™ 2000 was used as the benchmark control. Sonication and membrane extrusion were used to formulate emulsions with droplet size (d=120 nm) suitable for intravenous applications using peptide surfactant in the presence of Zn(II). Although these peptide emulsions are stable by themselves and in bovine serum, emulsion stability was found to be strongly affected by the presence of salt, EDTA, and proteins. The instability of AM1 emulsion in cell culture media has been a concern when it was subjected to in vitro cell culture tests. AM1-stabilised emulsion droplets were shown to be taken up by MCF-7 cells. However, siRNA when coupled with AM1 emulsion was not delivered into cells. Cytotoxicity studies showed that peptide surfactants did not exhibit high-level toxicity to CHO cells at the tested concentrations (0.25-2 mg mL-1). AM1 peptide-stabilised emulsions were mildly toxic to CHO cells but no toxicity was observed with MCF-7 cells. Future work could include evaluation of peptide emulsion-siRNA complex formation, and exploring the effects of different cell culture media compositions on emulsion stability and their relation to cytotoxicity.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 136-145).

The microbiological testing of foods is a well-established science. Due to the severity of foodborne pathogen illnesses, the widespread use and implementation of rapid detection methods in food testing labs is increasingly important. The first step for successful testing is sampling. Surfactants have been highly used in food microbiology, but there is not much, if any, published research about the use of fatty alcohols and chemical dispersants as aids in microbial separation. The microbial extraction efficiency of Escherichia coli K12 and Listeria innocua from hot dogs, spinach, and milk was measured using chemical additives (surfactants, fatty alcohols, and a chemical dispersant) in a buffer solution. Dry matter content was calculated using the oven method to determine how clean the sample was at the end of processing. Tween 80 at 0.01% was found to be the most effective additive for microbial recovery for each food matrix examined. The addition of fatty alcohols to surfactants also showed much promise in aiding separation as well as in minimizing dry matter in the final solution. However, the use of Buffered Peptone Water as the diluting agent resulted in very high recovery percentages without the need for additives.

Neste trabalho foram obtidos filmes de óxido de tungstênio pelo método sol-gel modificado, tendo como precursor o tungstato de sódio dihidratado (Na2WO4.2H2O) e como agente estruturante o surfactante cloreto de dodeciltrimetilamônio (DTAC). O comportamento dos sistemas em meio aquoso foi avaliado por medidas de pH, condutividade e viscosidade. Foram avaliadas duas metodologias de obtenção dos filmes de óxido de tungstênio: a primeira consistiu na obtenção de filmes de tungstato de sódio, através de sistemas contendo 10 mmol.L-1 de Na2WO4.2H2O em diferentes concentrações de DTAC, por casting, e conversão do tungstato de sódio a óxido de tungstênio pela acidificação dos filmes; a segunda metodologia consistiu na conversão dos sistemas aquosos contendo 20 mmol.L-1 de Na2WO4.2H2O, em diferentes concentrações de DTAC, em ácido tungstico, obtenção dos filmes por spin coating e, calcinação em presença de ar. Os filmes foram obtidos em substratos de silício (100) recobertos com dióxido de silício e avaliados por Difração de Raios-X, Espectrometria de retroespalhamento Rutherford, Espectroscopia Raman, Microscopia Eletrônica de Varredura e ensaios fotocatalíticos. As alterações na concentração precursor e agente estruturante não afetaram significativamente o pH e a viscosidade dos sistemas precursores. A determinação da concentração micelar crítica (cmc) do DTAC, obtida através da condutividade, foi de 13 mmol.L-1 e 9,88 mmol.L-1 para os sistemas contendo 10 e 20 mmol.L-1 de Na2WO4.2H2O, respectivamente. Em ambas metodologias o produto final foi o óxido de tungstênio em forma de disco e placas. As espessuras dos filmes obtidos na primeira metodologia variaram de 4 a 5 μm e as estruturas tiveram diâmetros médios de 4,37 μm e 114 nm. Na segunda metodologia as espessuras foram de 0,5-1,0 μm e as estruturas obtidas tiveram diâmetros médios em torno de 95-103 nm. Os filmes obtidos apresentaram atividade fotocatalítica, uma vez que duplicaram a velocidade da reação de degradação do corante alaranjado de metila em relação ao sistema sem o filme. / In this work tungsten oxide films have been obtained bymodified sol-gel method, with sodium tungstate dehydrate (Na2WO4.2H2O) as the precursor and the cationic surfactant dodecyltrimethylammonium chloride (DTAC) as structuring agent.The behavior in aqueous media of precursor/structuring agent systems was characterized by pH, conductivity and viscosity measurements. Two methods for obtaining tungsten oxide films were evaluated: the first consisted in obtaining sodium tungstate films from the systems containing 10 mmol.L-1 of Na2WO4.2H2O at different DTAC concentrations, by casting, converting the sodium tungstate to tungsten oxide; the second method consisted in the conversion of the aqueous systems containing 20 mmol.L-1 of Na2WO4.2H2O at different DTAC concentrations to tungstic acid, obtaining the films by spin coating and, posteriorly, calcination in the presence of air. The films were obtained on silicon substrate (100) with a 50 nm layer of silicon dioxide and were characterized by X-ray diffraction, Rutherford backscattering spectrometry, Raman spectroscopy, Scanning Electron Microscopy and photocatalytic tests. The precursor concentration and structuring agent do not affect significantly the pH and the viscosity of the precursor systems in aqueous media.The values of critical micelle concentration (CMC) of DTAC, obtained by the conductivity, were of13 mmol.L-1 and 9,88 mmol.L-1, for the systems containing 10 and 20 mmol.L-1 de Na2WO4.2H2O, respectively.In both adopted methods the final product is the tungsten oxide, with nano and micrometric structures in the form of discs and plates. The thickness of the films obtained in the first method varied from 4 to 5 μm and the structures presented an average diameter around 4,37 μm and 114 nm. The thickness of the films obtained with the second methodvariedfrom0,5to 1 μm and the structures presented an average diameter from 95 to103 nm.The obtained tungsten oxide films presented photocatalytic activity, since doubled the reaction rate of methyl orange dye degradation with respect to the system without the film.

Os cimentos de fosfato de cálcio (CFCs) formam uma pasta viscosa após a mistura de uma fase sólida (sal de fosfato de cálcio) com uma fase líquida (água ou uma solução aquosa). Esta pasta endurece, dando lugar a um precipitado que contenha um ou mais fosfatos de cálcio, que graças à sua formação à temperatura corporal evita uma resposta imunológica negativa do organismo. Embora uma das caraterísticas mais importantes dos cimentos de -TCP seja sua reabsorbilidade pelo organismo, a taxa de reabsorção In Vivo pode ser lenta devido à ausência de macroporos abertos. No presente trabalho foram obtidas estruturas macroporosas com presença de interconexões a partir da mistura de cimento de -TCP com uma fase líquida espumada. A fase líquida foi constituída de diferentes concentrações de hidrogenofosfato de sódio e um surfactante (Lutensol ON 110 ou Lauril Sulfato de Sódio), sendo espumada por agitação manual num sistema composto por 2 seringas conectadas por uma válvula de PVC. Após, foi acrescentado o pó de cimento, o qual foi misturado com a espuma no mesmo sistema. Verificou-se que as soluções com Lutensol apresentaram maior espumabilidade (218 – 400%) que as soluções com Lauril (63 – 209%). A difração de raios X evidenciou a transformação de -TCP em Hidroxiapatita deficiente em cálcio em todas as amostras após a imersão em solução de Ringer. As amostras preparadas com Lutensol apresentaram macroporos abertos com diâmetros maiores a 100m. Além disso foi observado que a macroestrutura final e o tamanho dos macroporos dos cimentos espumados varia em função das concentrações de fosfato e surfactante, além da proporção L/P. Por outro lado, a resistência a compressão das amostras macroporosas diminuiu com o aumento da porosidade total. Finalmente, foi observada a formação de uma camada continua de apatita sobre a superfície dos cimentos após imersão em SBF durante 21 dias. Este estudo sugere que as amostras de cimento de fosfato de cálcio espumadas com Lutensol possuem potencial para uso como arcabouços (scaffolds) para crescimento de tecidos. / Calcium phosphate cements (CPCs) form a viscous paste after mixing a solid phase (a calcium phosphate salt) with a liquid phase (water or an aqueous solution). This paste hardens, forming a precipitate with one or more calcium phosphates, which thanks to their formation at body temperature prevent a negative immune response. Even though one of the most important characteristics of -TCP cements is their resorbability in the body, their In Vivo resorption rate is low due to the lack of open macropores. In the present work, macroporous interconnected structures were obtained by mixing the -TCP cement with a foamed liquid phase. The liquid phase was composed of different concentrations of sodium hydrogenphosphate and a surfactant (Lutensol ON 110 or Sodium Lauril Sulfate), and it was foamed by manual agitation in a system of two syringes connected by a PVC valve. The cement powder was then added to the system and mixed with the foam likewise. Solutions with Lutensol showed better foamability (218 - 400%) than solutions with Lauril (63 - 209%). X-ray diffraction showed the transformation of -TCP into Calcium Deficient Hydroxyapatite in every sample after immersion in Ringer’s solution. Samples prepared with Lutensol showed open macropores with diameters greater than 100m. It was found that final macrostructure and size of macropores in the foamed cements vary according to phosphate and surfactant concentrations, as well as to the L/P ratio. It was also found that compressive strength of the macroporous samples decreased with the increase of the total porosity. Finally, a continuous apatite layer was observed on the surface of the cements after immersion in SBF for 21 days. This study suggests that the calcium phosphate cement samples foamed with Lutensol have potential to be applied as scaffolds for bone tissue regeneration.

Os cimentos de fosfato de cálcio (CFCs) formam uma pasta viscosa após a mistura de uma fase sólida (sal de fosfato de cálcio) com uma fase líquida (água ou uma solução aquosa). Esta pasta endurece, dando lugar a um precipitado que contenha um ou mais fosfatos de cálcio, que graças à sua formação à temperatura corporal evita uma resposta imunológica negativa do organismo. Embora uma das caraterísticas mais importantes dos cimentos de -TCP seja sua reabsorbilidade pelo organismo, a taxa de reabsorção In Vivo pode ser lenta devido à ausência de macroporos abertos. No presente trabalho foram obtidas estruturas macroporosas com presença de interconexões a partir da mistura de cimento de -TCP com uma fase líquida espumada. A fase líquida foi constituída de diferentes concentrações de hidrogenofosfato de sódio e um surfactante (Lutensol ON 110 ou Lauril Sulfato de Sódio), sendo espumada por agitação manual num sistema composto por 2 seringas conectadas por uma válvula de PVC. Após, foi acrescentado o pó de cimento, o qual foi misturado com a espuma no mesmo sistema. Verificou-se que as soluções com Lutensol apresentaram maior espumabilidade (218 – 400%) que as soluções com Lauril (63 – 209%). A difração de raios X evidenciou a transformação de -TCP em Hidroxiapatita deficiente em cálcio em todas as amostras após a imersão em solução de Ringer. As amostras preparadas com Lutensol apresentaram macroporos abertos com diâmetros maiores a 100m. Além disso foi observado que a macroestrutura final e o tamanho dos macroporos dos cimentos espumados varia em função das concentrações de fosfato e surfactante, além da proporção L/P. Por outro lado, a resistência a compressão das amostras macroporosas diminuiu com o aumento da porosidade total. Finalmente, foi observada a formação de uma camada continua de apatita sobre a superfície dos cimentos após imersão em SBF durante 21 dias. Este estudo sugere que as amostras de cimento de fosfato de cálcio espumadas com Lutensol possuem potencial para uso como arcabouços (scaffolds) para crescimento de tecidos. / Calcium phosphate cements (CPCs) form a viscous paste after mixing a solid phase (a calcium phosphate salt) with a liquid phase (water or an aqueous solution). This paste hardens, forming a precipitate with one or more calcium phosphates, which thanks to their formation at body temperature prevent a negative immune response. Even though one of the most important characteristics of -TCP cements is their resorbability in the body, their In Vivo resorption rate is low due to the lack of open macropores. In the present work, macroporous interconnected structures were obtained by mixing the -TCP cement with a foamed liquid phase. The liquid phase was composed of different concentrations of sodium hydrogenphosphate and a surfactant (Lutensol ON 110 or Sodium Lauril Sulfate), and it was foamed by manual agitation in a system of two syringes connected by a PVC valve. The cement powder was then added to the system and mixed with the foam likewise. Solutions with Lutensol showed better foamability (218 - 400%) than solutions with Lauril (63 - 209%). X-ray diffraction showed the transformation of -TCP into Calcium Deficient Hydroxyapatite in every sample after immersion in Ringer’s solution. Samples prepared with Lutensol showed open macropores with diameters greater than 100m. It was found that final macrostructure and size of macropores in the foamed cements vary according to phosphate and surfactant concentrations, as well as to the L/P ratio. It was also found that compressive strength of the macroporous samples decreased with the increase of the total porosity. Finally, a continuous apatite layer was observed on the surface of the cements after immersion in SBF for 21 days. This study suggests that the calcium phosphate cement samples foamed with Lutensol have potential to be applied as scaffolds for bone tissue regeneration.

Este trabalho investiga a obtenção de nanopartículas (NP) de óxido de ferro por coprecipitação, sua estabilização com surfactantes e caracterização quanto à morfologia e comportamento magnético. Atualmente, as NP estão sendo amplamente utilizadas para aplicações biomédicas, tais como contraste em imagens médicas e sistema de distribuição de drogas. Na síntese das NP foram investigados, parâmetros como a temperatura da reação, o pH da solução e a velocidade de agitação. O estudo da estabilidade comparou dois diferentes surfactantes: o ácido oleico (AO) e o polietileno glicol (PEG). As NP obtidas foram caracterizadas por difração de raios X (DRX), e quanto à sua morfologia por microscopia eletrônica por varredura (MEV) e microscopia eletrônica de transmissão (MET), a qual também proporcionou uma distribuição de tamanho de partículas, com variação entre 5 nm e 10,23 nm. A interação entre o óxido de ferro e seus revestimentos foi caracterizada por espectrocopia no infravermelho (FTIR) e espectrocopia Raman. O comportamento magnético das NP foi caracterizado por magnetometria de gradiente de força alternada (AGFM) e espectroscopia Mössbauer. Os resultados revelaram que as NP de óxido de ferro são tipicamente constituídas por magnetita ( ) revestida com AO e PEG e com um tamanho médio de cristalito entre 4,6 e 19,2 nm, calculado através da equação de Scherrer. O AGFM mostrou que as propriedades magnéticas das partículas foram mais eficientes para as NP com revestimento, do que com as NP sem revestimento, e o valor de magnetização de saturação (M) para a revestida com PEG foi maior quando comparado com a revestida com AO. A espectroscopia Mössbauer foi utilizada para confirmação do óxido de ferro como , para estimar tamanho de partícula quando os espectros são medidos a baixa temperatura e para análise do comportamento superparamagnético das partículas. / This work investigates the obtained nanoparticles (NP) iron oxide by coprecipitation stabilization with surfactants and characterize the morphology and magnetic behavior. Currently, the NP are being widely used for biomedical applications such as contrast in medical imaging and drug delivery system. In the synthesis of NP were investigated parameters such as the reaction temperature, the pH and stirring speed. The stability study compared two different surfactants: oleic acid (OA) and polyethylene glycol (PEG). The NP were characterized by X-ray diffraction (XRD), and morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which also provided a distribution of particle size, ranging from 5 nm and 10.23 nm. The interaction between the iron oxide and their coatings was characterized by infrared spectroscopy (FTIR) and Raman spectroscopy. The magnetic behavior of NP was characterized by magnetometry alternating gradient force (AGFM) and Mössbauer spectroscopy. The results show that the NP iron oxide are typically comprised of magnetite ( ) coated with PEG and AO and a crystallite size between 4.6 and 19.2 nm calculated by the Scherrer equation. The AGFM showed that the magnetic properties of the particles were more efficient for the NP uncoated than to NP coated, and the value of saturation magnetization (M) to coated with PEG was higher when compared to coated AO. Mössbauer spectroscopy was used to confirm the iron oxide as , to estimate the size of particle where the spectra are measured at low temperature and to analyze the behavior of superparamagnetic particles.