It was the objective of this project to provide a glass cleaner formulation for a wet wipe application with cleaning and anti-fogging properties. This glass cleaner formulation was developed for automotive glass i.e. interior of windscreens. This formulation relates to a glass cleaner with a composition comprising of: (a) a blend of amphoteric surfactants; (b) a solvent system with a combination of glycol ethers; and (c) an aqueous solvent system. This glass formulation must provide good cleaning properties while also providing good wetting and sheeting properties to assist with anti-fogging properties. The objectives were obtained using 2 specific approaches: The first was by using a blend of 2 amphoteric surfactants in an alkaline medium, allowing the glass surface to become more hydrophilic which will also assist with reduction of surface tension on the glass surface. The second was by using the glycol ethers that have good coupling properties and surface tension reducing properties. The formulation was evaluated using commercial standard test methods as per the industry. A predictive model was successfully obtained for each of the five criteria that were evaluated using the 25 formulations derived from the statistical design. There were variables and variable interactions that were antagonistic for some of the criteria which were found to be synergistic for others. To achieve satisfactory cleaning, the fogging rating had to be compromised.

Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic insulation, heat dissipation media and compact heat exchangers. In alignment with emerging additive manufacturing (AM) technology, realization of the structural applications of the lattice materials appears to be becoming faster. Considering the direction dependent material properties of the products with AM, by directionally dependent printing resolution, effective moduli of lattice structures appear to be directionally dependent. In this paper, a constitutive model of a lattice structure, which is an octet-truss with a base material having an orthotropic material property considering AM is developed. In a case study, polyjet based 3D printing material having an orthotropic property with a 9% difference in the principal direction provides difference in the axial and shear moduli in the octet-truss by 2.3 and 4.6%. Experimental validation for the effective properties of a 3D printed octet-truss is done for uniaxial tension and compression test. The theoretical value based on the micro-buckling of truss member are used to estimate the failure strength. Modulus value appears a little overestimate compared with the experiment. Finite element (FE) simulations for uniaxial compression and tension of octet-truss lattice materials are conducted. New effective properties for the octet-truss lattice structure are developed considering the observed behavior of the octet-truss structure under macroscopic compression and tension trough simulations.

In this project the adsorption ability of mesoporous magnesium carbonate (MMC) for copper (Cu), cobalt (Co), chromium (Cr) and arsenic (As) was evaluated. This was done by mixing MMC and dissolved metal (of different concentrations) and measuring the concentration of the solution before and after addition of MMC with Inductively coupled plasma optical emission spectroscopy. Besides MMC, “ordinary” magnesium carbonate (MgCO_3) was evaluated for comparison. Furthermore, the MMC was characterised with various instruments before and after adsorption of the metals. The adsorption experiments established that MMC was able to adsorb large amounts of Cu, Co and As while MgCO_3 was not. Moreover, it was discovered that both materials adsorbed equally large amounts of Cr. At higher concentrations of Cu and Co the uptake capacity of MMC suddenly dropped. However, for As, it was determined that MMC reached saturation at a concentration of ~22 mg/L. An adsorption experiment of a mixture of metals of 20 mg/L of each metal could not conclude anything about the selectivity of MMC, but the experiment revealed that MMC was able to adsorb all of Cu, Co and As rapidly at this concentration. The characterisation of MMC before adsorption revealed an amorphous structure and a high porosity. The structure of MMC after adsorption of Cu went from amorphous to crystalline and after adsorption of Co and As the structure also became crystalline, but of a lower degree than after adsorption of Cu. Furthermore, it was discovered that ion exchange also occurred along with adsorption.

Synthesis of materials with certain properties for targeted applications is an ongoing challenge in materials science. One of the most interesting classes of solid-state materials that have been recently introduced with the potential to address this is metal-organic frameworks (MOFs). MOFs chemistry offers a higher degree of control over materials to be synthesized utilizing various new design strategies, such as the molecular building blocks (MBBs) and the supermolecular building layers (SBLs) approaches. Depending on using predetermined building blocks, these strategies permit the synthesis of MOFs with targeted topologies and enable fine tuning of their properties. This study examines a number of aspects of the design and synthesis of MOFs while exploring their possible utilization in two diverse fields related to energy and pharmaceutical applications. Concerning MOFs design and synthesis, the work presented here explores the rational design of various MOFs with predicted topologies and tunable cavities constructed by pillaring pre-targeted 2-periodic SBLs using the ligand-to-axial and six-connected axial-to-axial pillaring strategies. The effect of expanding the confined spaces in prepared MOFs or modifying their functionalities, while preserving the underlying network topology, was investigated. Additionally, The MBBs approach was employed to discover new modular polynuclear rare earth (RE)-MBBs in the presence of different angular polytopic ligands containing carboxylate and nitrogen moieties with the aid of a modulator. The goal was to assess the diverse possible coordination modes and construct highly-connected nets for utility in the design of new MOFs and enhance the predictability of structural outcomes. The effect of adjusting ligands’ length-to-width ratio on the prepared MOFs was also evaluated. As a result, the reaction conditions amenable for reliable formation of the unprecedented octadecanuclear, octanuclear and double tetranuclear RE-MBBs were isolated, and their corresponding MOFs were successfully synthesized and characterized. Regarding the applications of MOFs, gas sorption behavior of the novel prepared MOFs was studied to establish structure-property relationships that elucidate the effect of using different metals and/or ligands on tuning various properties of the prepared compounds. Furthermore, the magnetic properties of selected MOFs were investigated. Besides, as a proof-of-concept, known neutral and anionic MOFs were considered as potential drug delivery carriers.

Cellulose nanofibrils are a biobased and renewable material with potential to be used in many different applications. Such applications include air filtration, absorption of liquids, and thermal insulation.  To be used for these applications the cellulose nanofibrils must form a porous and dry material. However, maintaining some degree of porosity after drying is difficult, since the fibrils are extracted in liquid and tend to collapse into a dense material upon drying. Certain methods have proven effective for making a dry porous material from cellulose nanofibrils, but these are often expensive and not suitable for large scale production. The aim of this project is to test possible methods for making a highly porous cellulose nanofibril-based material. These methods must be environmentally sustainable and suitable for large scale production. An extensive screening has been conducted with the aim of identifying methods resulting in materials with high porosity. The obtained materials have been analysed further to give a more thorough understanding of the porosity as well as other characteristics. The results indicate that cross-links in the material strengthen the structure, and that drying samples from water always results in complete collapse or very dense materials while drying samples from certain solvents other than water results in more porous materials. The analysed materials had very different porosities, some of which were relatively high. The most porous material analysed by Brunauer-Emmett-Teller gas adsorption had a surface area of 9.5 m2/g. This project gives insight into how cross-linking chemistries and treatment with different solvents and pH affect the resulting cellulose nanofibril-based material, as well as knowledge about which methods can be used to successfully produce dry porous cellulose nanofibril-based materials.

This thesis summarizes our latest findings on liquid-solid equilibria for fluids in confined spaces. In the first part of the thesis we introduce a microscopic lattice model which we have developed for the exploration of the freezing and melting phenomena in mesoporous solids with arbitrary geometries of the pore spaces. By applying this model to materials with well-ordered pore structures we (i) establish the mechanisms of the freezing and melting transitions and identify the equilibrium and metastable transition branches for different boundary conditions, (ii) illuminate the role of thermodynamic fluctuations, and (iii) find rigorous equations governing the transition temperatures for the lattice model considered. In the second part of the thesis the results obtained with the ordered pore systems are used for an in-depth analysis of the transitions occurring in geometrically disordered porous solids. First, by considering the ink-bottle pore geometry the efficacies of the different phase transition mechanisms established in the first part are elucidated. As a particularly important result, it is shown that thermodynamic fluctuations may alter the transition mechanisms. In the light of these findings the freezing and melting behaviors in statistically disordered porous materials are discussed. In the third part of the thesis several experimentally-relevant topics are considered and the potentials of the microscopic model for evaluation of the experimental data are demonstrated.

The thesis at hand is a collection of the publications written and co-authored by the author on the subject of fluid phase equilibria and dynamics in porous materials as studied with computational methods. The first part addresses fluid adsorption in confined mesoporous spaces with a particular focus on hysteresis phenomena. For this purpose, first the sorption mechanisms in canonical pore segments and simple interconnected pores were studied. Based on those insights, a statistical theory describing the phase equilibria in large-scale disordered pore systems was developed, yielding novel understanding of the sorption phenomena in complex mesoporous materials and promising future application for the characterization of these pore spaces. The second part of this thesis considers the mass transfer properties of hierarchical porous solids combining two different porosities. Here, the relationship between the structural biporous composition of the host material and the molecular dynamics were studied using specifically developed statistical simulations. Particularly, micro-mesoporous materials, hollow core-shell silica nanoparticles, and mixed matrix membranes were considered. For each case, comparison to experimental data led to a deeper understanding of the underlying transport processes. Each of the two chapters is preceded by a short introduction into the subject focused on presenting the concepts used in the corresponding publications.:1 Introduction 2 Adsorption in mesoporous solids 2.1 Filling dynamics of closed end nanocapillaries 2.2 Modeling the influence of side stream and ink bottle structures on adsorp- tion/desorption dynamics of fluids in long pores 2.3 Phase transitions in disordered mesoporous solids 3 Diffusion in hierarchical biporous materials 3.1 Mesopore-promoted transport in microporous materials 3.2 Transport properties of hierarchical micro-mesoporous materials 3.3 Diffusion and molecular exchange in hollow core-shell silica nanoparticles 3.4 An untrodden path: Versatile fabrication of self-supporting polymer- stabilized percolation membranes (PSPMs) for gas separation 3.5 Short-time diffusion behavior of Brownian particles in confining potentials Bibliography Author contributions Acknowledgements / Vorliegende Dissertation ist eine Sammlung der vom Autor verfassten und mitverfassten Publikationen über fluide Phasengleichgewichte und Fluiddynamik in porösen Materialien, untersucht mit Hilfe von computergestützten Methoden. Der erste Teil handelt von Flüssigkeitsadsorption in mesoporösen Porenräumen mit Schwerpunkt Hysteresephänomene. Dabei wurden zuerst Sorptionsmechanismen in kanonischen Porensegmenten und einfachen zusammengesetzten Porenmodellen untersucht. Aufbauend auf diese Erkenntnisse wurde dann eine statistische Theorie entwickelt, welche es ermöglicht, Phasengleichgewichte in komplexen ungeordneten Porenräumen zu beschreiben. Die entwickelte Methode erlaubt ein erweitertes Verständnis über Sorptionsphänomene in komplexen mesoporösen Materialien und die Anwendung in der Charakterisierung dieser Porenräume erscheint aussichtsreich. Der zweite Teil der Dissertation beschäftigt sich mit den Gastransporteigenschaften von hierarchischen, aus zwei Porösitäten zusammengesetzten Festkörpern. Dabei stand vor allem der Zusammenhang zwischen der biporösen Komposition des Materials und der Moleküldynamik im Vordergrund, untersucht unter Zuhilfenahme eigens entwickelter statistischer Simulationen. Betrachtet wurden insbesondere mikro-mesoporöse Materialien, hohle Siliziumdioxid-Nanopartikel und Membranen mit gemischter Matrix. Tiefergehendes Verständnis über die zugrundeliegenden Gastransportprozesse wurde im Vergleich mit experimentellen Ergebnissen erreicht. Beide Kapitel werden durch eine kurze Einführung in die jeweilige Thematik und die den nachfolgenden Publikationen zugrundeliegenden Konzepten ergänzt.:1 Introduction 2 Adsorption in mesoporous solids 2.1 Filling dynamics of closed end nanocapillaries 2.2 Modeling the influence of side stream and ink bottle structures on adsorp- tion/desorption dynamics of fluids in long pores 2.3 Phase transitions in disordered mesoporous solids 3 Diffusion in hierarchical biporous materials 3.1 Mesopore-promoted transport in microporous materials 3.2 Transport properties of hierarchical micro-mesoporous materials 3.3 Diffusion and molecular exchange in hollow core-shell silica nanoparticles 3.4 An untrodden path: Versatile fabrication of self-supporting polymer- stabilized percolation membranes (PSPMs) for gas separation 3.5 Short-time diffusion behavior of Brownian particles in confining potentials Bibliography Author contributions Acknowledgements

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La fabrication de matériaux ductiles insère généralement des impuretés dans leurs compositions microscopiques. Ces impuretés peuvent se détacher de la matrice environnante et même se fissurer lors d’une déformation progressive. En raison de la résultante incapacité de ces particules indésirables à supporter toute contrainte, ces matériaux ductiles sont, de manière équivalente, supposés être poreux. Il a été largement démontré que la porosité joue un rôle fondamental dans les mécanismes de la rupture ductile. Depuis les années 1970, de nombreux modèles micromécaniques ont été proposés dans le but de décriremathématiquement ces mécanismes. Parmi eux, le célèbre modèle de Gurson combine la technique d’homogénéisation avec le théorème cinématique de l’analyse limite pour estimer le critère de plastification macroscopique et la loi d’évolution de la porosité des matériaux ductiles poreux. Cependant, le modèle de Gurson, ainsi que la plupart de ses extensions, ne tient compte que de la rupture ductile isotrope. Le but du présent travail est donc de contribuer à la conception de critères de plastification pour la rupture ductile des milieuxporeux anisotropes. Trois contributions principales tirant parti d’hypothèses similaires à celles du modèle de Gurson sont ici proposées. La première contribution est l’évaluation de l’influence de la morphologie des vides sur les critères de plastification macroscopique de ces classes de matériaux. La deuxième est l’inclusion d’un critère de plastification anisotrope dans la matrice du matériau, de sorte que le comportement macroscopique présente une anisotropie induite par cette matrice, y compris pour les cavités sphériques. Le troisième et dernier progrès consiste à généraliser le critère de plastification de la matrice afin d’inclure une classe de fonctions de plastification basée sur des transformations linéaires. Cette classe de fonction a été largement employée avec succès pour représenter des alliages d’aluminium à haute résistance. Les résultats ici présentés soulignent la cohérence et la robustesse des trois formulations. En outre, le rôle de la porosité sur la modélisation de la plasticité des alliages d’aluminium incite à poursuivre les travaux sur la caractérisation expérimentale des paramètres d’anisotropie. / The manufacturing of ductile materials generally inserts impurities into their microscopic composition. These impurities may detach from the surrounding matrix and even crack along progressive deformation. Due to the consequent incapacity of these undesirable particles of supporting any stress, these ductile materials are equivalently assumed to be porous. Porosity has been effectively shown to play a fundamental role in the mechanisms of ductile fracture. Many micromechanical models have been proposed since the 1970s with the aim of mathematically describing these mechanisms. Among them, the acclaimed Gursonmodel combines the averaging homogenization technique with the kinematic theorem of Limit Analysis to estimate the macroscopic yield criterion and porosity evolution law of porous ductile materials. However, the Gurson model and most of its extensions only account for isotropic ductile fracture. Thus, the purpose of the present work is to contribute to the conception of yield criteria for anisotropic porous ductile rupture. Three main contributions are hereby proposed by profiting from similar hypothesis to those of the Gurson model. The first contribution is the assessment of the influence of void morphology on overall yield criteria for those classes of materials. The second is the inclusion of ananisotropic yield criterion in the material matrix so that the macroscopic behavior present matrix-induced anisotropy even for spherical cavities. The third and last advancement consists of generalizing the material matrix yield criterion of the Gurson model in order to comprehend a linear transformation-based class of yield functions that has been widely used to represent specific high strength aluminum alloys. The results hereby presented highlight the consistency and robustness of the three formulations. Moreover, the role of the porosity on the modeling of yield behavior of aluminum alloys encourages further work regarding experimental parameter characterization.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographies. / by Mostafa Ameen Foda. / Sc.D.