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

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.

Plastics have become a universal material for use in a myriad of commercial and consumer products. One such product, exterior siding, is the focus of this project. Although siding products were originally made from wood, vinyl siding, which offered superior performance, was introduced in the 1950’s. More recently, polypropylene (PP) siding has been introduced; PP provides a stronger product, which allows for deeper patterns and better edge detailing. PP siding, compared to traditional wood siding, doesn’t warp, crack, or degrade as easily with extended exposure to the elements, and is cheaper to maintain. However, even plastic siding must be coated. The requirements of a coating for siding are good adhesion, durability, and a suitable appearance. However, polypropylene, like many plastics, has a low surface energy, making wetting and coating adhesion difficult. One of the many ways to increase the surface energy of polypropylene, thus increasing wettability and adhesion, is plasma treatment. The primary focus of this project was to study how plasma treatment improved adhesion of a water-reducible coating. This coating represented a product used in commercial siding. The surface tension of the panels was increased from ~30 dynes/cm to 60+ dynes/cm with plasma treatment. This increased the adhesion of the coating to the polypropylene panel from virtually no adhesion to almost perfect adhesion. Adhesion was tested according to ASTM D3359, the crosscut adhesion test. Pull-off adhesion testing (ASTM D4541-09) was also conducted, using a Deflesko PosiTest AT-A automatic adhesion tester. The average force needed to remove a dolly from a plasma treated panel was 233 ± 47 psi (1,605 ± 325 kPa), compared to 92 ± 26 psi (634 ± 179 kPa) for non-treated and corona treated panels. The sponsor of the project provided Cal Poly with 16 different compositions of polypropylene containing different amounts of UV stabilizers, adhesion promoters, and lubricants. The effect of substrate composition on coating adhesion and performance was measured. Crosscut adhesion testing results revealed all polypropylene compositions improved from virtually no adhesion to perfect adhesion after plasma treatment. Pull-off adhesion testing revealed the adhesion force of all compositions improved from less than 100 psi to greater than 200 psi. One polypropylene composition, Category 16, resulted in unusually high pull-off forces. This composition was investigated using X-ray Photoelectron Spectroscopy (XPS) and FT-IR spectroscopy. XPS was used to examine the surface composition between non-treated and plasma treated PP panels. It was observed that plasma treatment provides a larger amount of oxygen species and nitrogen when compared to untreated panels. The category 16 panels did not reveal any significant surface differences compared to the category 7 panels (which represented the standard production material). FT-IR spectroscopy of the category 16 panels also showed no unusual characteristics. The secondary focus of this project was to study the durability of coated, plasma treated polypropylene siding. Accelerated weathering testing was conducted on 12 of the 16 different compositions of polypropylene. Changes in gloss and the LAB colorspace of coated, plasma treated polypropylene panels of different compositions, upon exposure to long-term weathering conditions, were monitored via ASTM G53 using a Q-Panel lab product QUV/se weathering tester. After 2400 hours, all PP compositions tested shared negligible changes in color, but the gloss of each category panel showed a steady increase. An approach to improve durability of siding is to apply a clearcoat over already coated PP panels. This approach was tested in a limited manner by adding a clearcoat to coated, plasma treated polypropylene panels. These panels were then exposed to a variety of common, household cleaning agents using a modified double rub test (ASTM D4752 and ASTM D5402). The samples with a clearcoat showed improved cleaning agent resistance compared to samples without the clearcoat.

Die Benetzbarkeit und Nichtbenetzbarkeit von Oberflächen durch eine Flüssigkeit sind faszinierende und wichtige Phänomene in Wissenschaft und Technologie. Jüngst wurde entdeckt, dass Partikel die Benetzung einer Wasseroberfläche durch ein Öl unterstützen können. Es wurde eine Theorie entwickelt, das Prinzip der zu beschreiben. In der vorliegenden Doktorarbeit wurde diese Theorie im Experiment sowohl qualitativ als auch quantitativ untersucht, wobei zwei Arten von Kieselgelpartikeln Verwendung fanden. Mit Hilfe einer Reihe unregelmäßig geformter Partikel mit variierender Hydrophobie wurde der Einfluss der Oberflächenhydrophobie der Partikel auf die partikel-assistierte Benetzung untersucht. Es wurde herausgefunden, dass die Partikel mit höchster Hydrophilie Linsen aus reinem Öl bilden, während die Partikel in die Wasserphase abtauchen. Die Partikel mit größter Hydrophobie hingegen bewirken die Ausbildung von kleinen Bereichen, in denen Öl und Partikel eine stabile homogene Schicht formen. Für Partikel mit mittlerer Hydrophobie wurden beide Phänomene beobachtet. Diese drei verschiedenen Beobachtungen bestätigen, dass die Oberflächenhydrophobie der Partikel das Benetzungsverhalten des Öls auf der Wasseroberfläche bestimmen. Für die unregelmäßig geformten Partikel war aufgrund des unbekannten Kontaktwinkels ein direkter Vergleich zur Theorie nicht möglich. Um die Theorie quantitativ zu prüfen, wurden sphärische Partikel synthetisiert und ihre Oberflächen mit Hilfe von zehn Silanisierungsmittel modifiziert. Anschließend wurde ein Vergleich der experimentellen Ergebnisse mit dem entsprechenden theoretischen Phasendiagramm durchgeführt. Die Untersuchungen zeigten, dass die theoretischen Vorhersagen zum Großteil mit den experimentellen Ergebnissen übereinstimmen. Es wurden alle Fälle der Benetzung beobachtet, die auch in der theoretischen Beschreibung berücksichtigt wurden. Darüber hinaus wurden auch Abweichungen von der Theorie festgestellt. Haben die Partikel ähnliche Affinitäten zur Luft/Öl- und Öl/Wasser-Grenzfläche, hängt die Beschaffenheit der Benetzungsfilme zusätzlich vom Oberflächendruck ab. Deshalb könnte es notwendig sein, die einfache Theorie zu erweitern um den beschriebenen Beobachtungen Rechnung zu tragen. / Wetting and de-wetting of surfaces by a liquid are fascinating and important phenomena in science and technology. Recently, it was discovered that particles can assist the wetting of a water surface by an oil, and a theory describing the principle behind particle assisted wetting was developed. In this thesis, the theory was experimentally investigated qualitatively and quantitatively by using two series of silica particles. The influence of the surface hydrophobicity of the particles on particle assisted wetting was investigated by a series of irregular shaped particles with varying hydrophobicity. By applying mixtures of particles and oil to a water surface, it was found that for the most hydrophilic particles, only lenses of pure oil formed, with the particles being submerged into the aqueous phase. The most hydrophobic particles helped to form patches of stable homogenous mixed layers composed of oil and particles. For particles with intermediate hydrophobicity, lenses and patches of mixed layers were observed. These three different observations verified that the hydrophobicity of the particle surface determines the wetting behaviour of the oil at the water surface. For the irregular shaped particles with unknown contact angles with liquid interfaces, no direct comparison to the theory was possible. To test the theory quantitatively, a series of spherical particles was synthesized and their surfaces were modified by ten kinds of silane coupling agents; then the experimental results were compared with the corresponding theoretical phase diagram. It indicated that the theory agrees at large with the experimental results. All scenarios of wetting layers taken into account in the theoretical description were observed. In the fine print, deviations from the theory were also observed. If the particles have similar affinities to air/oil and oil/water interfaces, the experimentally observed morphology of the wetting layers depends in addition on the surface pressure. It might therefore be necessary to extend the simple theoretical picture to take these observations into accounts.

A commercial epoxy was modified by adding fluorinated poly (aryl ether ketone) and in turn metal micro powders (Ni, Al, Zn, and Ag) and coated on mild steel. Two curing agents were used; triethylenetetramine (curing temperatures: 30 oC and 70 oC) and hexamethylenediamine (curing temperature: 80 oC). Variation in tribological properties (dynamic friction and wear) and surface energies with varying metal powders and curing agents was evaluated. When cured at 30 oC, friction and wear decreased significantly due to phase separation reaction being favored but increased when cured at 70 oC and 80 oC due to cross linking reaction being favored. There was a significant decrease in surface energies with the addition of modifiers.

In this Study, the surface energy was investigated for six penetration grade 70/100 bitumen binders. Wilhelmy Plate and the Sessile Drop were used to determine the contact angles. The purpose of this study was to compare the Wilhelmy Plate method with the Sessile Drop method, and to compare the significance of Owens-Wendt model with the significance of Acid Base model by correlating surface energy components. Better R2 –values were found for surface energy components by using the Owens-Wendt model than by using the Acid Base model. It was concluded here that Owens-Wendt model is a better model for determining surface energy components of bituminous binders than the Acid Base model since bituminous binders have low energy surfaces. For both instruments: When using Diiodomethane as a probe liquid the biggest variations among the binders were observed. When using water as a probe liquid the least variations among the binders were observed. The advancing contact angles for water determined for these six bitumen binders using the Wilhelmy plate method do not exceed the 90 degree by much, suggesting that bitumen is not extremely hydrophobic. The Sessile Drop method offers a faster and more convenient way to measure the surface energy components of bitumen binders than the Wilhelmy Plate method.

With the use of a process-orientated ecosystem model andmeasurements conducted at different Swedish coniferous forestsites, abiotic and biotic interactions between tree and soilwere identified and related to governing factors. Two differentmodelling approaches to describe soil temperatures at two sitesincluding hydrological transects were tested (I). The approachin which both canopy and soil were considered proved to be amore flexible tool to describe soil temperatures, especiallyduring snow-free winter periods. Five sites along a climatetransect covering Sweden were used to describe soil carbon poolchanges during an 80-year period simulation (II). The dynamicmodelling approach, with a feedback between abiotic and bioticsub-models, was successful in describing simplified patterns offorest stand dynamics and furthermore in differentiatingbetween climate and nitrogen availability factors. The largereffect of nitrogen availability compared to climate on soilcarbon pool changes was clearly shown. Keywords:SPAC; soil surface energy balance; Norwayspruce; canopy; LAI; climate; nitrogen; CoupModel

This study evaluated the potential of using the Surface Energy Balance Algorithm for Land (SEBAL) as a means for estimating evapotranspiration (ET) for local and regional scales in Southern Idaho. The original SEBAL model was refined during this study to provide better estimation of ET in agricultural areas and to make more reliable estimates of ET from other surfaces as well, including mountainous terrain. The modified version of SEBAL used in this study, termed as SEBALID (lD stands for Idaho) includes standardization of the two SEBAL "anchor" pixels, the use of a water balance model to track top soil moisture, adaptation of components of SEBAL for better prediction of the surface energy balance in mountains and sloping terrain, and use of the ratio between actual ET and alfalfa reference evapotranspiration (ETr) as a means for obtaining the temporal integration of instantaneous ET to daily and seasonal values. Validation of the SEBALID model at a local scale was performed by comparing lysimeter ET measurements from the USDA-ARS facility at Kimberly, Idaho, with ET predictions by SEBAL using Landsat 5 TM imagery. Comparison of measured and predicted ET values was challenging due to the resolution of the Landsat thermal band (120m x 120 m) and the relatively small size of the lysimeter fields. In the cases where thermal information was adequate, SEBALID predictions were close to the measured values of ET in the lysimeters. Application of SEBALID at a regional scale was performed using Landsat 7 ETM+ and Landsat 5 TM imagery for the Eastern Snake Plain Aquifer (ESP A) region in Idaho during 2000. The results indicated that SEBALID performed well for predicting daily and seasonal ET for agricultural areas. Some unreasonable results were obtained for desert and basalt areas, due to uncertainties of the prediction of surface parameters. In mountains, even though validation of results was not possible, the values of ET obtained reflected the progress produced by the refinements made to the original SEBAL algorithm.

No description available.

Diels-Alder chemistry was utilized to manipulate the surface energy of glass substrates in reversible manner. Glass slides and capillaries were functionalized with hydrophobic dieneophiles resulting in a non-wetting surface. A retro Diels-Alder reaction facilitated by the thermal treatment of the surface’s function to cleave the hydrophobic dieneophile and resulted in the fabrication of a hydrophilic surface. Contact angle (CA) measurements were used as preliminary measurements for monitoring the changes in surface energy exhibited during the initial hydrophobic state (CA - 70±3°), after attachment of the dieneophile creating a hydrophobic state (CA - 101±9°) followed by reestablishment of the hydrophilic state (CA - 70±6°) upon cleavage of the Diels-Alder adduct. The treatments developed on flat glass surfaces were transferred to glass capillaries, with effective treatment confirmed by fluid column measurements. Effective flow gating was developed in the capillaries via patterning of the surface with hydrophilic/hydrophobic regions. Finally, attempts to create self-pressurizing capillaries were unsuccessful due to pronounced contact angle hysteresis for the hydrophobic surface treatment. Indium-tin oxide (ITO) substrates were functionalized with successive surface intiated atom transfer radical polymerization (SI-ATRP) and electropolymerization. A novel hybrid styrenic/thiophene monomer (ProDOT-Sty) was synthesized and employed in the polymerization events. This unique monomer and combination of polymerization methods allowed for the templation of electropolymerized poly(3,4-alkyleneoxythiophene) brushes by first creating a poly(styrene) backbone via SI-ATRP. An ITO electrode functionalized with poly(ProDOT-Sty) brushes grafted from the ITO surface via SI-ATRP was analyzed via cyclic voltammetry which clearly indicated the electropolymerization event beginning at approximately +0.7 V vs Fc/Fc+. Photo patterning of the phosphonic acid ATRP initiator immobilized on the ITO surface was undertaken in order to create a surface that would limit growth of the polymer species to a patterned area for facile film brush thickness characterization via atomic force microscopy (AFM) at a later time. This was accomplished via lithography with ultraviolet radiation (UV) and was confirmed via scanning electron microscopy (SEM). A nanohetero structure composed of platinum tipped cadmium selenide seeded, cadium sulfide nanorods (CdSe@CdS-Pt NRs). CdSe quantum dots (QDs) with variable sizes were prepared by adjusting reaction temperatures and times. CdS nanorods were then grown utilizing the CdSe QDs as seeds. Various lengths of the CdSe@CdS NRs were produced that ranged from ~25 nm to ~135 nm. Investigation of the influence of the various synthetic conditions of the nanorod synthesis led to the conclusion that the ratio of CdSe seeds to Cd and S precursors could be manipulated in order to influence the length to which the nanorods grew. Pt tips were attached to an end of the CdSe@CdS nanorods as photocatalytic hydrogen production sites. TEM was utilized to characterize the different types of nanoparticles at each stage of assembly.