The modification of plastic and rubber matrices with nano-scale particles can produce completely new properties with regard both to the mechanical and the functional characteristics of the matrix materials. These are derived from the special surface and interface properties of the nano particles. Nano technology is therefore regarded globally as an ‘enabler’ for innovative products and processes. It is seen as a key technology of the future and is expected to provide an innovation thrust in virtually every technical segment, particularly in production, automotive, energy and IC technology. On the other hand, nano technology still provides a number of major challenges for research and development, especially with regard to the production and compounding of nano particles, the specific improvement of the mechanical properties of matrix materials, and the generation of specific functions in connection with matrix materials with the aid of nano particles. Nano particles* can be spherical, cylindrical or platelet-shaped. Examples of nano-scale particles are SiO2, TiO2, ZnO2 nano particles, layered silicates (montmorillonite), and carbon nanotubes (Single and Multi Wall Carbon Nanotubes SWCNT, MWCNT) as well as organic and high molecular-weight particles. Nano particles are produced from macroscopic structures by plasma or laser ablation in the gas phase or from molecular structures in the liquid phase (sol phase). Key requirements here are the prevention of agglomeration of the produced nano particles and ensuring exfoliation of the layered silicates. This is often done by modifying the particle surface or replacing the cations of the layered silicates with voluminous organic cations. Compounding of the nano particles and the homogeneous dispersion of the particles (good distribution while retaining the nano-scale structure) is essential for obtaining a successful result in the composite with the polymer matrix. Nano-scale fillers act as heterogeneous nuclei in semi-crystalline plastics, and thus determine the morphology of the composites. The most common application for nano particles to date is as fillers in plastic matrices to improve the mechanical properties. The aim here is predominantly to achieve high stiffness and strength/hardness combined with high toughness and high heat resistance. The effect of carbon black and SiO2 in car tyres has been known for a long time. Other promising new openings for nano particles are to increase the heat stability of rubber in under-the-bonnet applications in the automotive industry. Further examples include reinforcement of the polymer matrix with carbon nanotubes (CNT) in sports goods (tennis racquets and golf clubs) and reinforcement of the matrix in carbon fibre composites. Materials of this kind can be used in all kinds of vehicles to reduce weight and thus save fuel through the substitution of metal materials. The use of CNTs as fillers results in composites with high electrical conductivity (for example, CNT-filled polyoxymethylene attains a maximum specific volume resistance of 30 Ώ cm) combined with improved flow behaviour in the melt and higher temperature stability without any significant loss of mechanical properties. In addition, CNT-filled polymer matrices not only have good antistatic properties, they also afford improved thermal conductivity and can be made transparent. Metal oxide particles in surface coatings increase the scratch resistance, offer protection from wear and corrosion, and also create an anti-reflection effect and improved UV absorption. Magnetic nano particles in a polymer matrix can, through application of a magnetic alternating field and subsequent heating, lead to thermally activated crosslinkage. Exfoliated layered silicates as platelet-shaped nano particles in plastic matrices improve fire and flame protection and have a high barrier effect in plastic films. In this connection, mention should also be made of nano-porous, high molecular-weight foams, which have increased insulation capability and are of particular importance for lightweight construction. Nano-porous membranes (nano filters) can be used for water demineralisation and for the elimination of bacteria, viruses and toxins (heavy metal salts, dioxins) from contaminated water. Apart from that, special effects are to be expected from plastic modifications with nano-scale particles in terms of their functional properties. This is still a very special challenge for research and development. Polymers with metal oxide clusters as nano-scale fillers – organic-inorganic hybrid materials – are expected to display special optical, electrical and magnetic properties as are required for polymer electronics, storage media, photovoltaics, organic light-emitting diodes (OLEDs), displays and sensors. On the matter of the safety of nano particles, it has to be said that we are constantly surrounded by biogenic, natural and anthropogenic fine dust (aerosols). Nano particles that are permanently integrated into a matrix no longer exist as nano-scale particles that could adhere to aerosols. Also during use – e.g. through abrasion – it is to be expected that the nano particles remain permanently adhered to matrix fragments and are not released as nano particles. This must, however, be ensured for the respective product. During production, particular attention must be paid to the release of nano particles into the environment. For this reason, the nano particles are normally processed in a liquid medium and/or even in agglomerated form. To be able to estimate the hazard potential of nano particles, the stability and lifetime of the particles as nano particles and their behaviour in biological systems must be clarified. Relevant studies are being conducted on a broad basis, and they will help to minimise potential health and ecological hazards that emanate from products containing nano-scale particles. *Nano particles have, at least in one dimension, an expansion of lower than 100 nm, i.e. less than 1/10 000 nm or smaller than 1/1000th of the diameter of a human hair. - Vita Prof. Dr. Dr. h.c. Heinrich Hartwig Höcker