Clusterwachstum auf Oberflächen spielt eine wichtige Rolle bei der Entwicklung neuartiger Materialien in der Nanotechnologie. Für ein Verständnis der vielfältigen möglichen Clusterstrukturen muss insbesondere die Wachstumskinetik fern des thermodynamischen Gleichgewichts berücksichtigt werden. Im ersten Teil dieser Arbeit werden auf Grundlage umfangreicher kinetischer Monte-Carlo-Simulationen Größenverteilungen von Clustern für verschiedene Wachstumsmodelle untersucht. Es wird gezeigt, dass Ratengleichungen die Größenverteilungen korrekt vorhersagen können, wenn Parameter für den Einfang von Teilchen in ihrer vollen funktionalen Abhängigkeit von der Clustergröße, Bedeckung und dem D/F-Verhältnis aus Diffusionskoeffizient D und Aufdampfrate F erfasst werden. Des Weiteren werden selbstkonsistente Theorien für die Einfangparameter und Theorien für das Verhalten skalierter Größenverteilungen im Grenzfall großer D/F-Verhältnisse kritisch überprüft. Im zweiten Teil der Arbeit wird ein Modell für das Wachstum von Fullerenen auf dielektrischen Kristalloberflächen entwickelt. Mit Hilfe eines neuen Mechanismus der unterstützten Entnetzung wird die Entstehung merkwürdiger Clustermorphologien in diesen Systemen erklärt, welche zuvor in verschiedenen Experimenten gefunden wurden. Kinetische Monte-Carlo-Simulationen des Modells mit Parametern, die für das Wachstum von Fullerenen auf der Kalziumfluorid(111)-Oberfläche angepasst wurden, liefern eine hervorragende Übereinstimmung mit experimentellen Beobachtungen.

Omniphobic surfaces found in nature have great potential for enabling novel and emerging products and technologies to facilitate the daily life of human societies. One example is the water and even oilrepellent cuticle of springtails (Collembola). The wingless arthropods evolved a highly textured, hierarchically arranged surface pattern that affords mechanical robustness and wetting resistance even at elevated hydrostatic pressures. Springtail cuticle-derived surfaces therefore promise to overcome limitations of lotus-inspired surfaces (low durability, insufficient repellence of low surface tension liquids). In this review, we report on the liquid-repellent natural surfaces of arthropods living in aqueous or temporarily flooded habitats including water-walking insects or water spiders. In particular, we focus on springtails presenting an overview on the cuticular morphology and chemistry and their biological relevance. Based on the obtained liquid repellence of a variety of liquids with remarkable efficiency, the review provides general design criteria for robust omniphobic surfaces. In particular, the resistance against complete wetting and the mechanical stability strongly both depend on the topographical features of the nano- and micropatterned surface. The current understanding of the underlying principles and approaches to their technological implementation are summarized and discussed.

Wasserstoffbeladene metallische Multischichten wurden mit der tomographischen Atomsonde (TAP) und der Sekundärionenmassenspektrometrie (SIMS) auf ihre chemische zusammensetzung mit Auflösungen auf Subnanometerskala untersucht. Bei den verwendeten Methoden werden nach dem Prinzip der Flugzeit-Massen-Spektrometrie die Proben atomlagenweise abgetragen und analysiert. Die Ergebnisse werden präsentiert und im Hinblick auf die Wassertstoffverteilung an den Grenzflächen diskutiert. Gleichgwichtsverteilungen können bei Temperaturen unterhalb von 60 k gemessen werden. Bei höheren Temperaturen führt die hohe Mobilität des Wassertstoffs zu einer Segregation des Wasserstoffs an der Oberfläche der Probe. Die während des Abtrags der Metalle geschaffenen Oberflächen der Multischichtsysteme bieten dann dem Wasserstoff energetisch günstige Oberflächenplätze ...

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The problem of generating a surface triangulation from a set of points with normal information arises in several mesh processing tasks like surface reconstruction or surface resampling. In this paper we present a surface triangulation approach which is based on local 2d delaunay triangulations in tangent space. Our contribution is the extension of this method to surfaces with sharp corners and creases. We demonstrate the robustness of the method on difficult meshing problems that include nearby sheets, self intersecting non manifold surfaces and noisy point samples.

The problem of generating a surface triangulation from a set of points with normal information arises in several mesh processing tasks like surface reconstruction or surface resampling. In this paper we present a surface triangulation approach which is based on local 2d delaunay triangulations in tangent space. Our contribution is the extension of this method to surfaces with sharp corners and creases. We demonstrate the robustness of the method on difficult meshing problems that include nearby sheets, self intersecting non manifold surfaces and noisy point samples.

Omniphobic surfaces found in nature have great potential for enabling novel and emerging products and technologies to facilitate the daily life of human societies. One example is the water and even oilrepellent cuticle of springtails (Collembola). The wingless arthropods evolved a highly textured, hierarchically arranged surface pattern that affords mechanical robustness and wetting resistance even at elevated hydrostatic pressures. Springtail cuticle-derived surfaces therefore promise to overcome limitations of lotus-inspired surfaces (low durability, insufficient repellence of low surface tension liquids). In this review, we report on the liquid-repellent natural surfaces of arthropods living in aqueous or temporarily flooded habitats including water-walking insects or water spiders. In particular, we focus on springtails presenting an overview on the cuticular morphology and chemistry and their biological relevance. Based on the obtained liquid repellence of a variety of liquids with remarkable efficiency, the review provides general design criteria for robust omniphobic surfaces. In particular, the resistance against complete wetting and the mechanical stability strongly both depend on the topographical features of the nano- and micropatterned surface. The current understanding of the underlying principles and approaches to their technological implementation are summarized and discussed.

The design of functional materials with complex properties is very important for different applications, such as coatings, microelectronics, biotechnologies and medicine. It is also crucial that such kinds of materials have a long service lifetime. Unfortunately, cracks or other types of damages may occur during everyday use and some parts of the material should be changed for the regeneration of the initial properties. One of the approaches to avoid the replacement is utilization of self-healing materials. The aim of this thesis was to design a self-repairable material with superhydrophobic and switchable properties using colloidal particles. Specific goals were the synthesis of colloidal particles and the preparation of functional surfaces incorporated with the obtained particles, which would exhibit a repairable switching behavior and repairable superhydrophobicity. In order to achieve these goals, first, methods of preparation of simple and functional colloidal particles were developed. Second, the behavior of particles at surfaces of easy fusible solid materials, namely, paraffin wax or perfluorodecane, was investigated.

The design of functional materials with complex properties is very important for different applications, such as coatings, microelectronics, biotechnologies and medicine. It is also crucial that such kinds of materials have a long service lifetime. Unfortunately, cracks or other types of damages may occur during everyday use and some parts of the material should be changed for the regeneration of the initial properties. One of the approaches to avoid the replacement is utilization of self-healing materials. The aim of this thesis was to design a self-repairable material with superhydrophobic and switchable properties using colloidal particles. Specific goals were the synthesis of colloidal particles and the preparation of functional surfaces incorporated with the obtained particles, which would exhibit a repairable switching behavior and repairable superhydrophobicity. In order to achieve these goals, first, methods of preparation of simple and functional colloidal particles were developed. Second, the behavior of particles at surfaces of easy fusible solid materials, namely, paraffin wax or perfluorodecane, was investigated.

Icing is an important problem, which often leads to emergency situations in northern countries. The reduction of icing requires a detailed understanding of this process. In this work, we report on a systematic investigation of the effects of geometry and chemical properties of surfaces on the formation of an ice layer, its properties, and thawing. We compare in detail icing and ice thawing on flat and rough hydrophilic and hydrophobic surfaces. We also show advantages and disadvantages of the surfaces of each kind. We demonstrate that water condenses in a liquid form, leading to the formation of a thin continuous water layer on a hydrophilic surface. Meanwhile, separated rounded water droplets are formed on hydrophobic surfaces. As a result of slower heat exchange, the freezing of rounded water droplets on a hydrophobic surface occurs later than the freezing of the continuous water layer on a hydrophilic one. Moreover, growth of ice on hydrophobic surfaces is slower than on the hydrophilic ones, because ice grows due to the condensation of water vapor on already formed ice crystals, and not due to the condensation on the polymer surface. Rough hydrophobic surfaces also demonstrate a very low ice adhesion value, which is because of the reduced contact area with ice. The main disadvantage of hydrophobic and superhydrophobic surfaces is the pinning of water droplets on them after thawing. Flat hydrophilic poly(ethylene glycol)-modified surfaces also exhibit very low ice adhesion, which is due to the very low freezing point of the water–poly(ethylene glycol) mixtures. Water easily leaves from flat hydrophilic poly(ethylene glycol)-modified surfaces, and they quickly become dry. However, the ice growth rate on poly(ethylene glycol)-modified hydrophilic surfaces is the highest. These results indicate that neither purely (super)hydrophobic polymeric surfaces, nor ‘‘antifreeze’’ hydrophilic ones provide an ideal solution to the problem of icing.