The tailoring of surface properties of metal oxide nanoparticles is highly important to exploit their benefits in an optimal way for diverse applications. For example, in polymer matrix nanocomposites one of the most critical aspects is the interaction of the particles with the matrix, which is determined by the chemistry of the particle surface and can be adjusted by attachment of organic ligands. Whilst many empirical solutions have been presented for specific combinations of particles and matrix, generalized approaches are not available yet. As a versatile and arbitrary method to permanently modify the surface of metal oxide nanoparticles, we present a two-step approach and prove its applicability for the versatile adjustment of surface properties of two types of nanoparticles.

The application of modified Al 2 O 3 nanoparticles for thin coatings is investigated to improve especially the mechanical characteristics by cross-linking the particles using an additive, together with the formulation parameters as well as the crosslinking kinetics. In general, the experiments demonstrate that the mechanical properties, like hardness and scratch resistance, can be enhanced via particle surface modification in combination with a cross-linking additive. Specifically, the optimal additive concentration was determined in order to obtain coatings with improved mechanical and constant optical properties. These results were related to the structure formation and cross-linking behavior. Mechanisms were identified for this series of experiments to explain how the particles bond with each other and how the coating structure is formed by using different additive ratios.

No abstract

Lithium-ion batteries (LIBs) provide the largest source of electrical energy storage today. This paper covers the use of comminution processes and, thus, crushers and mills for particle breakage and dispersing, as well as classifiers for particle separation within the process chain, from the raw material to the final lithium battery cell and its recycling at end of life. First of all, the raw materials for the active material production have to be produced either by processing primary raw materials, or by recycling the spent lithium batteries. The end-of-life battery cells have to be shredded, the materials separated and then milled in order to achieve the so-called black mass, which provides a secondary material source with very valuable components. Using these materials for the synthesis of the cathode active materials, milling has to be applied in different stages. The natural graphite, increasingly used as anode material, has to be designed in mills and classifiers for achieving targeted properties. Nanosized silicon is produced by nanomilling using stirred media mills as a primary option. Conductive additives for LIBs, like carbon black, have to be dispersed in a solvent with machines like planetary mixers, extruders or stirred media mills. In the future, mechanochemical synthesis of solid electrolytes will especially require additional application of comminution processes.

No abstract

No abstract

Titania nanoparticle-based thin films are highly attractive for a vast range of commercial applications. Although their application on polymer-based substrates is particularly appealing, the requirement of low process temperatures results in low mechanical stability. Highly crystalline anatase nanoparticles were used as the building blocks for coatings through a two-stage process. The main benefits of this method, over the more common sol-gel ones, are the relatively low temperature required for the production of metal oxide coatings, allowing the use of polymer-based substrates, and the defined crystallinity of the resulting thin films. Although in several cases moderate temperatures can be utilized for drying the films, the mechanical stability of the respective coatings remains a critical issue. In this contribution, we present a strategy to achieve network formation between TiO nanoparticles in a preformed thin film on the basis of the cross-linking of the functionalized nanoparticles. In the first stage, the nanoparticles were functionalized by dicarboxylic acids, concurrently leading to a stable colloidal dispersion that could be utilized for dip-coating to obtain TiO thin films with high homogeneity and optical transparence. During the second stage, the films were immersed in a solution of a diamine as the linker molecule, to achieve cross-linking between the nanoparticles within the film. It is demonstrated that indeed covalent bonding was realized and functional coatings with significantly enhanced mechanical properties were obtained by our strategy.

Polymere Nanokomposite erfahren heutzutage zunehmende Bedeutung für die Erzeugung funktioneller Beschichtungen. Zu diesem Zweck werden maßgeschneiderte modifizierte Nanopartikel in eine Harzmatrix eingebracht und die Eigenschaften einer so erzeugten Beschichtung wesentlich verbessert. In dieser Arbeit wird der Zusammenhang der gesamten Prozesskette, von der Synthese bis zur Charakterisierung der Schichten, mit besonderem Blick auf die partikuläre Oberflächenchemie untersucht. Auf diese Weise kann dieser Einfluss aus einer Hand überprüft und Randeffekte weitgehend vermieden werden.Schlagwörter: Easy-to-clean, Nanokomposite, Oberflächenchemie, Partikelmodifizierung, Prozesskette Improvement of Surface Properties of Polymeric Coatings by Nanoparticles with Tailored Surface ModificationToday, polymer nanocomposites are of growing interest for the production of functional coatings. For this purpose, tailored and surface-modified nanoparticles are incorporated into a polymeric resin. Thereby, the characteristics of the used system can be altered and desired properties can be enhanced. In this work, the whole process chain, from synthesis to characterization of the coating, was examined with special attention to the surface chemistry of the nanoparticles. Hereby, the influence of the surface modification of the particles can be investigated while avoiding side effects.