Oberflächenmodifizierung von Carbon Nanotubes mittels technischer Niederdruckplasmen

Carbon nanotubes (CNTs) are a nanomaterial featuring extraordinary properties such as a low density - comparable to that of polymers -, high mechanical properties, as well as electrical conductivity, temperature stability, and thermal conductivity. Since they are also chemically widely inert and show low to no dispersability in most substances, a surface modification is imperative for an improved processability and to achieve a phase adhesion. The work at hand resulted from a close cooperation of the University of Stuttgart (Institute for Interfacial Engineering, IGVT) and the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB). It describes plasmachemical methods to attain such a modification and their advantages over conventional wet-chemical attempts. Based on specific and semi-quantitative analysis methods developed in this context for the first time, dependencies of the composition of the surface from the plasma process parameters process gas, treatment duration, pressure, and load were identified and respective optima for the preferred generation of certain surface functional groups were ascertained. Via fluiddynamical modelling and experimental investigations also a plasma reactor design was developed allowing the direct modification of powdery material and significantly outperforming currently existing systems with respect to efficiency, scalability, and ease of integration into the production process. Finally, the effectiveness of the performed modifications was validated in further application investigations proving an improved dispersion and significantly increased phase adhesion