A inserção de aditivos em sistemas nanométricos tem como objetivo usual a estabilização destes materiais. A distribuição do aditivo nas interfaces é fundamental para o controle do balanço energético e das características da nanopartícula. Neste trabalho, foi estudado o efeito termodinâmico da inserção de Zn2+ e Sn4+ nos pós de SnO2 e ZnO, respectivamente, sintetizados pelo método dos precursores poliméricos baseado em Pechini. A quantificação do excesso de interface pela lixiviação ácida e o estudo da evolução do tamanho das partículas e de suas áreas de superfície e de contorno de grão, permitiram calcular a distribuição do aditivo no sistema e avaliar sua influência em cada região onde este estava localizado. À 500°C, para baixas concentrações, há a solubilização dos aditivos na rede, promovendo o crescimento das nanopartículas. Para as concentrações acima de 0,05 mol%, o aditivo tende a se concentrar no contorno de grão e na superfície, promovendo uma estabilidade a estas regiões, possibilitando nanopartícula menores no que as dos pós sem aditivo e com baixa aglomeração. O ensaio cinético reforçou a ideia da correlação entre estabilidade e distribuição do aditivo nas interfaces, além de mostrar um efeito de aceleração do processo de estabilização com o aumento da concentração de aditivos. Também foi possível calcular o calor de segregação para o contorno de grão (?HsegrCG= 48,8 J.mol-1) e superfície (?HSsegr= 37,0 J.mol-1), o que permitiu determinar as energias das interfaces, mostrando que a estabilização provocada pela inserção de aditivos esta diretamente associada a diminuição destas energias. / The inclusion of additives in nanometric systems has the usual purpose of stabilizing these materials. This distribution in the interfaces is critical to the control of energy balance and nanoparticle characteristics. In this work, we studied the thermodynamic effect of the inclusion of Zn2+ and Sn4+ in the powders of SnO2 and ZnO, respectively, synthesized by the polymeric precursor method based on Pechini. The quantification of interface excess by acid leaching and the study of the evolution of particle size, surface areas and grain boundary, allowed to calculate the distribution of the additive in the system and evaluate its influence in each region where it was located. At 500 °C, for low concentrations, there is a solubilization of additives in the bulk, promoting growth of the nanoparticles. For concentrations above 0.05 mol%, the additive tends to concentrate on grain boundary and surface, promoting the stability of these regions. This stability enables smaller nanoparticles and with low agglomeration. The kinetic assay strengthened the idea of correlation between stability and distribution of the additive in the interfaces, besides showing an accelerating effect of the stabilization process by increasing the concentration of additives. It was also possible to calculate the heat of segregation of the grain boundary (?HCGsegr = 48.8 J.mol-1) and surface (?HSsegr = 37.0 J.mol-1), which allowed to determine the energies of the interfaces. This showed that the stabilization brought about by the inclusion of additives is directly associated with the reduction of these energies.

Esta tese apresenta o estudo do efeito do solvente acetato de etila e acetona no comportamento em solução dos polímeros acetato butirato celulose (CAB) e acetato butirato carboximetil celulose (CMCAB) e nas características dos seus filmes finos obtidos pela técnica de revestimento rotacional ou por adsorção. As medidas de viscosidade e espalhamento de raio-X a baixo ângulo (SAXS) mostraram que o acetato de etila é um melhor solvente para CAB e CMCAB do que a acetona. A caracterização dos filmes foi feita através de medidas de elipsometria, microscopia de força atômica (AFM), espectrocospia vibracional por geração de soma de freqüências (SFG) e medidas de ângulo de contato. Os filmes de CMCAB obtidos por revestimento rotacional são mais espessos quando preparado em acetona do que em acetato de etila. Imagens de AFM mostraram que os filmes de CMCAB oriundos de soluções em acetato de etila são mais homogêneos e lisos do que aqueles preparados a partir de acetona. Medidas de SFG comprovaram a forte afinidade da acetona com SiO2/Si, mostrando que esse solvente cria uma nova camada para os filmes de CAB e CMCAB. Os valores de energia superficial calculados para CAB e CMCAB foram semelhantes ~ (49,0 ± 0,5) mJ/m², sendo a contribuição da componente dispersiva maior que a da componente polar. A adsorção das proteínas lisozima, albumina do soro bovino (BSA), concanavalina A e jacalina foram mais pronunciadas sobre os filmes de CMCAB do que sobre CAB. Indicando que a presença do grupo carboximetil (CM) contribui significativamente no processo de adsorção das biomoléculas. O efeito da rugosidade dos filmes de CAB e CMCAB sobre o processo de adsorção das proteínas foi estudado. No caso do CMCAB, a adsorção das proteínas foi mais pronunciada sobre o filme rugoso do que sobre o filme mais liso. Entretanto, para os filmes de CAB a rugosidade não teve um efeito significativo na adsorção das proteínas / The effect of ethyl acetate and acetone on the solution behavior of cellulose acetate butyrate (CAB) and carboxymehtylcellulose acetate butyrate (CMCAB) and on the characteristics of films obtained either by spin coating or adsorption was investigated. Viscosity and small angle X-ray scattering (SAXS) measurements showed that ethyl acetate is a better solvent than acetone for CAB e CMCAB. Films were characterized by means of ellipsometry, atomic force microscopy (AFM), sum frequency generation (SFG) and contact angle measurements. Spin-coated films of CMCAB from ethyl acetate solutions were thicker than those deposited from acetone solutions. AFM images revealed that CMCAB spin coated films from ethyl acetate solutions were homogeneous and flat. However, films obtained from solutions in acetone were very rough. SFG spectra showed that acetone binds strongly to SiO2/Si wafers, creating a new surface for CAB and CMCAB films. Surface energy values determined for spin-coated CAB and CMCAB were similar ~ (49,0 ± 0,5) mJ/m² with the dispersive component larger than the polar component. The adsorption of lysozyme, bovine serum albumin (BSA), concanavalin A and jacalin was more pronounced onto CMCAB films than that onto CAB films. Indicating that carboxymethyl group favored the adsorption process. The influence of surface roughness of CAB and CMCAB on protein adsorption has been investigated. In the case of CMCAB, protein adsorption was morepronounced onto rough films than that onto flat films. However, the roughness of CAB films exerted no significant influence on proteins adsorption

Au cours de ce travail, nous avons décrit et mis en œuvre la fabrication de surfaces nanostructurées d’alumine par anodisation de feuilles d’aluminium de très grande pureté. Les paramètres morphologiques caractérisant la membrane d’oxyde que sont le diamètre des pores, leur profondeur et leur espacement sont finement contrôlés par les paramètres expérimentaux. Ces surfaces nanotexturées ont permis l’étude approfondie de l’interaction solide-liquide au sein des pores et de la physique de la ligne de contact devant composer avec les nano-aspérités de surface. Ces deux éléments ont pu être appréhendés par des mesures d’angles de contact à l’équilibre et d’hystérésis de mouillage. La modélisation des résultats a montré l’inadéquation des modèles classiques de CASSIE, WENZEL ou de capillarité à cette situation. L’adjonction du terme controversé de tension de ligne permet de bonnes prévisions. Nous montrons que cette interprétation n’est pas unique ; une diminution de l’énergie de surface due à la forte courbure des pores conduit à des résultats identiques. Une investigation théorique a été menée par l’intégration des forces de VAN DER WAALS. La baisse de l’énergie de surface est prévue mais dans des proportions insuffisantes. Le modèle peut être amélioré. Les mesures d’hystérésis ont dévoilé le pouvoir adhésif des surfaces nanoporeuses. À cause des forces de capillarité dans les pores, la ligne de contact ne peut jamais reculer. Les angles d’avancée ont montré que la ligne de contact a une épaisseur négligeable devant la dizaine de nanomètre. Elle peut en outre parfaitement contourner les pores, imprimant de fortes courbures à l’interface liquide-gaz à la base de la goutte. Sa forme tridimensionnelle a été abordée au travers d’un modèle numérique restant à perfectionner. / In this work, we have described and carried out the fabrication of nanostructured alumina surfaces by anodizing highly pure aluminum foils. The pore diameter, depth and spacing are finely controled through experimental parameters. These nanotextured surfaces allowed a thorough study of the solid-liquid interactions within the pores and of the contact-line constrained by the surface nanoasperities. Equilibrium contact-angle and wetting hysteresis measurements were helpful to apprehend them. Modeling the results has revealed the inability of classical CASSIE, WENZEL and capillarity models to properly match the situation. Adding the controversial line-tension term solves the problem and provides good predictions. Anyway, this interpretation is not unique. A lower surface energy within the pores due to their strong curvature yields the same modeling quality. This case has been theoretically investigated through the integration of VAN DER WAALS’ forces. A surface-energy decrease has been calculated but it is not as strong as required. The model still can be improved. Hysteresis measurements have highlighted the nanoporous surfaces are strongly adhesive. Because of the pore size, the capillarity is very marked and keeps the contact line from receding. The advancing contact angles have shown that the contact-line thickness is negligible with respect of ten nanometres. In addition, it can circumvent the pore openings which involves strong liquid–gas interface curvatures at the drop base. The three-dimensional liquid–gas interface shape has been studied with a numerical model that still has to be enhanced.

På grund av världens växande befolkning och urbaniseringen blir problem relaterade till fenomenet urbana värmeöar mer och mer påtagliga. Eftersom urbana parker kan minska påfrestningen skapad av urbana värmeöar kan de vara ett kraftfullt verktyg vid klimatdesign i städer. Temperaturen nära en yta bestäms av energiutbytet mellan ytan och luften ovanför och det är därför nödvändigt att man förstår energibalansen vid markytan för att kunna hantera parkernas mikroklimat. Syftet med det här arbetet var att studera skillnaderna mellan energibalansen för olika ytor i parken och i dess omgivning och att relatera skillnaderna i energibalanserna till temperaturskillnaderna. Mätningarna utfördes under tre klara sommardagar i parken Humlegården i centrala Stockholm. Mätutrustningen var monterad på en kärra som flyttades från mätplats till mätplats. Mätplatserna representerade olika typiska ytor i Humlegården och i dess omgivning: en skuggad och en öppen gräsmatta, en öppen och en skuggad grusyta och två asfaltytor, varav en löper i nord-sydlig riktning och en i öst-västlig riktning. Energiflödena beräknades med hjälp av data för luft- och yttemperatur, vindhastighet, luftfuktighet och nettostrålning. Resultaten visade att den tydligaste skillnaden mellan gräs- och grusytorna i parken var att gräsytorna hade ett större nedåtriktat latent värmeflöde under natten och ett mindre markvärmeflöde under hela dygnet. Den mest distinkta skillnaden mellan de skuggade och öppna ytorna i parken var att de skuggade ytorna hade mindre energiflöden under dagen och att de till skillnad från de andra ytorna hade ett nedåtriktat sensibelt värmeflöde under dagen. Den största skillnaden mellan ytorna i och utanför parken var att asfaltytorna hade ett större uppåtriktat sensibelt värmeflöde och markvärmeflöde under natten. Under natten var den svalaste mätplasten den öppna gräsmattan, vilken också var den enda mätplasten med ett nedåtriktat sensibelt värmeflöde under natten. Jämfört med de andra ickeskuggade mätplasterna hade den öppna gräsmattan ett mindre markvärmeflöde. Varmaste mätplasterna under natten var asfaltytorna som även hade ett större uppåtriktat sensibelt och markvärmeflöde än de andra ytorna. Under dagen var de skuggade ytorna i parken de svalaste platserna. De var de enda ytorna med ett nedåtriktat sensibelt värmeflöde och nettostrålningen vid ytan var mindre än för de flesta andra mätplatser. / The world’s growing population and the increasing urbanization has made problems related to the urban heat island phenomenon to become more pronounced and since urban parks reduce the stress produced by the urban heat island they can be powerful tools in urban climate design. The temperature near the surface in a park is determined by the energy exchanges between the surface and the air above and it is therefore necessary to understand the surface energy balance of parks to intelligently manage their thermal microclimate. The objectives of this work were to study how the energy balances differ between different surfaces inside parks and in their built-up surroundings and to relate the surface energy balances to temperature differences. Measurements were conducted during three clear summer days in the park Humlegården located in central Stockholm. The measuring instruments were mounted on a cart, which was transported from observation site to observation site. The observation sites represented typical surfaces found in an urban park and its surroundings: one shaded and one open grass surface, one open and one shaded gravel surface and two paved surfaces representing streets running in the north-south and east-west directions respectively. The energy fluxes were calculated using air and surface temperatures, wind speed, air humidity and net radiation data. The most pronounced differences between the shaded and open surfaces in the park was that the shaded surfaces in general had smaller energy fluxes during daytime and that they had a downward directed sensible heat flux while the open surfaces had an upward directed sensible heat flux during the day. The most significant difference between the grass and the gravel surfaces in the park was that the grass surfaces had a bigger downward directed latent heat flux during the night and a smaller ground heat flux during both day and night. The largest differences between the surfaces inside the park and those in its built-up vicinities were that the paved surfaces had a larger upward directed sensible and ground heat flux during the night than the other surfaces. During the day the north-south directed paved site had a downward directed ground heat flux that was much larger than the ground heat flux for the other sites. The coolest site during the night was the non-shaded grass surface, which was the only site with a downward directed sensible heat flux during the night. Compared to the other nonshaded sites the open grass surface had a much smaller ground heat flux. Warmest sites during the night were the paved surfaces, which had a larger upward directed sensible and ground heat flux than the other surfaces. At the built-up sites the walls also contributed with sensible heat flux, i.e. the total sensible heat flux in the built-up area was larger than what comes from the street surface only. During the day the shaded surfaces in the park were the coolest sites. The shaded surfaces had less net radiation compared to the other non-shaded surfaces and were the only sites that had a downward directed sensible heat flux.

Papers are coated in order to improve the properties of the surface, to improve printability and to include new functionalities like barriers properties. Typical coating formulation contains a high number of components, some are made from minerals and others are manufactured from petroleum. The barrier properties of today's paper based packages are plastics and/or aluminum             foil. Environmentally friendly substitutie of these nonrenewable materials are needed.  Nanocellulose is a promising material                 and of a growing interest as an alternative to petroleum-based materials, since nanocellulose films/coatings have been shown to have excellent mechanical and barrier properties.   This project aimed to evaluate nanocellulose in combination with minerals in paper coatings. The project had two approaches. One was to evaluate the barrier properties of MFC coatings with mineral included. The second part was about coatings for           printing matters, and evaluation of the possibility to replace petroleum-based binders in the coating color with MFC. Barrier properties were evaluated by measuring the air permeability of the coatings. The properties of the coating affecting the         printability in offset printing examined was the surface energy, the gloss, the roughness of the coatings, the strength and the offset ink setting.   Carboxymethylated nanocellulose formed denser films and had superior barrier properties compared with enzymatically pretreated nanocellulose. Adding of minerals did not affect the barrier properties of the MFC coatings to a significant extent.         Therefore, minerals cannot be added to enhance the barrier but it can be added to reduce the cost of the coating process without losing any barrier properties.                                 The print quality depends on how the ink interacts with the coating. These coatings did have a relatively high surface energy, which is preferable for printing with waterborne ink. It was also shown that the absorption abilities increased when the amount of MFC was increased. However, offset printing demands high surface strength and addition of MFC in the coating color                     drastically decreased the strength. This means that the coatings produced in this work are not strong enough and thereby not           suitable for offset printing. However other printing technologies put lower demand on surface strength and are still possible.

Development of new scientific disciplines such as bioengineering and micro-nano engineering adopting nonconventional materials requests innovative methodologies that can accurately measure the mechanical properties of soft biological materials and characterize surface energy and adhesion properties of them, independent of measurement conditions. One of emerging methods to measure the deformation of materials under stress is digital image correlation (DIC) technique. As a noncontact strain measurement method, DIC has the advantages of prevention of experimental errors caused by the use of contact type sensors and of flexibility in its application to soft materials that are hard to be tested by conventional method. In the first part of the thesis, 2 dimensional and 3 dimensional DIC codes were developed and optimized, and then applied to two critical applications: 1) determining the stress-strain behaviour of polydimethylsiloxane (PDMS) sample, as a model soft material, using the optical images across large deformation region, and 2) detecting the stiffness variation within the gel mimicking the breast tumour using ultrasound images. The results of this study showed the capability of DIC as a strain sensor and suggested its potential as a diagnosing tool for the malignant lesion causing local stiffness variation. In the characterization of surface energy and adhesion properties of materials, two most common methods are contact angle measurement and JKR-type indentation test. In the second part of the thesis, the experimental set-up for these methods were developed and verified by using the PDMS in static (quasi equilibrium) state. From the dynamic tests, it showed its possible usage in studying adhesion hysteresis with respect to speed. The adhesion hysteresis was observed at high speed condition in both contact angle measurement and JKR-type indentation tests.

Today approximately 10 % of fermented milk products stick to the packaging material inner surface, and therefore it is not possible to pour all of the dairy product from the package. This is both an economical and environmental issue. The product loss is expensive for consumer and makes recycling of package less effective. As they do not yet exist the development of packaging materials to which fermented milk products stick less, it would make it possible to both save money and protect our environment. The aim of this work was to provide knowledge and understanding of the important factors involved in the phenomenon when fermented milk products adhere to the inner surface of a packaging material. Studies were done on materials having different surface properties, such as polarity and relative oxidation. They were incubated in fermented milk and other dairy products varying in fat concentration and protein type up to 168 h. The systems were investigated gravimetrically, with Fourier Transform Infra Red/Attenuated Total Reflectance Spectroscopy, Scanning Electron Microscopy and Contact Angle measurements. Fermented milk contains amphiphilic components and therefore can interact both with polar and non-polar surfaces, such that the relative oxidation of the surface does not contribute to the adhesion. The adhesion of fermented milk is an equilibrium reaction, which depend on the fat concentration before equilibrium as well as the protein concentration after equilibrium. The adhesion seems to follows the Vroman effect, with smaller molecules associating faster and thereby adhering to the surface initially, but are displaced by larger molecules that associates slower as times passes.

This study is based on the Owen-Wendt-Rabel and Kaelble method¡Aand we using several substrates which's surface energy is already known to determind the surface eneygy of liquid. We measure the contact angle of the liquid on the substract to calculate the dispers part and the polar part of the surface enerfy. And then we compare the system with different sets of substrates and choose one proper set to be the standard substrates.Finally we test the system by several common liquid which¡¦s surface energy is already known,and measure the surface energy of liquid crystal. In this study,we found that the surface energy of the liquid crystal on an alignment layer is anisotropy,and discuss requirements of the standard substrate.

Accurately and efficiently characterizing the material properties of hot mix asphalt (HMA) is critical to the design and development of pavements that can experience repeated loading for long periods of time and resist fatigue cracking. The Calibrated Mechanistic with Surface Energy (CMSE) method of design to preclude this primary type of distress requires that the HMA material be tested using the Relaxation Modulus (RM) and Repeated Direct Tension (RDT) tests to determine the material properties required for accurate calculations. The RM test requires considerable time to complete and provides results with relatively high variability. Further research has lead to the development of the Viscoelastic Characterization (VEC) test, from which the RM master curve can be developed. Material properties from the RM master curve can be easily determined and applied in the CMSE method. The modified repeated direct tension (RDT*) test removes rest periods and unwanted healing from the RDT test. The RDT* test also allows the dissipated pseudo strain energy (DPSE) to be separated into permanent deformation and fatigue cracking energies. The rate of change in DPSE associated with fatigue can then be applied in the CMSE method. Data sets for these tests are extensive and time consuming to analyze. Microsoft Excel spreadsheet macros were developed to reduce the time required for analysis from an estimated 10 hours to approximately 8 minutes. Testing of 14 different samples showed that the VEC and RDT* tests still required some adjustments in order to get accurate results. The rate of loading in the VEC test must be reduced to allow sufficient testing time to obtain the required data. The RDT* test requires a decrease in the controlling strain levels from 80 mu-epsilon and 350 mu-epsilon to 20 mu-epsilon and 175 mu-epsilon for the undamaged and damaged portions of the test, respectively. Testing of a sample using the new VEC and RDT* test recommendations showed that the recommended changes provided better results. Samples were undamaged where required and damaged portions of the test ran to completion without causing compression or sample failure. Material properties can be accurately determined and applied in the CMSE method.

Vertical alignment liquid crystal display has the advantages of wide view angle, high contrast and good response time. Today vertical alignment liquid crystal display get flourishing development, and Multi-Domain Vertical Alignment (MVA) technology is progressive. In this report we would find an alignment materiel which could be fabricated easily, low cost and good E-O characteristic. The use of dimenthysiloxane (PDMS) in fabrication of microfluidic channels technology in biotechnology has the advantages of characteristics foregoing. In this study PDMS was used as LC vertical alignment materiel. We used the MVA structure and ASV structure to align LC direction because PDMS cannot be rubbed. In experiment we found that PDMS exhibited different surface energies when it was baked in different temperature. The results of measuring the pre-tilt angle in the different surface energy conditions are similar. ASV LC samples were fabricated using PDMS alignment layer. MVA LC cells were made using high viscosity PDMS. We found the characteristic of paper white at CIE chromaticity diagram in the ASV LC sample without any color filter and color correction technology.