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Functional nanofillers with controlled release properties for innovative polymers

Michael Noeske - Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM)

Modern composite materials like adhesives, coatings or membranes basically are composed of highly developed organic polymer systems and solid fillers. In case of chemically reactive and curable polymers, inorganic fillers contribute to application properties in the uncured state of reactive polymer systems, and mechanical or permeation properties of the resulting cured composites. With these composite materials typically exhibiting a thickness of some tens of micrometers, filler particles inside the layers will have to be small microparticles or even nanoparticles.

For the development of innovative fillers, the nano-technological concepts of function integration and interphase design are implemented. Such design requires knowledge and tools focused on the interactions between solid surfaces and organic monomers or polymers. Computer-based simulation may be applied to identify and finally tailor material combinations which then are introduced into chemical synthesis and engineering. Aiming at designing host/guest systems, the host will have to provide on the one hand an appropriate geometry of interspaces like pores in zeolites or galleries in layered silicates and on the other hand energetically favorable binding sites as determined by the chemical surface composition. The guest will have to feature a specific functionality (like initiation of chemical reactions, or corrosion inhibition) at least in the liberated state and, especially in controlled release systems, a mobility which can be triggered by external, e.g. environmental, stimuli.

Within the course, the students will be introduced to chemical reactions principles for curing reactive polymer mixtures, to the geometrical and chemical properties of micro and nanoscale particulate host systems, to tailoring the host surface properties, e.g. by silane (self-assembled) monolayers, and to dispersing the functional nanoparticles within reactive polymer mixtures. Aiming at surface characterisation of host materials and composites, surface spectroscopy (mainly XPS, X-ray photoelectron spectroscopy) will be introduced methodically.

Tutorials will comprise questions and approximate calculations (using pocket calculators) for seizing orders of magnitude of important factors for material synthesis or molecular geometries as well as for XPS measurements (rules of thumb for peak positions). Already measured XPS spectra for polymer bulk substances and for thin film adsorbates (films as discussed by colleagues in the workshop) will be evaluated.

Abstract Noeske