Modification of polymer surfaces with respect to their lubrication properties

Abstract

The aim of this work is to utilise and combine the knowledge gained in the study of model systems and the inspiration from biological systems for the investigation of the interfacial properties of a new type of system, polymer surfaces exposing a self assembled polymeric surfactant. An analogous system, polyethylene, though with no surface coating, is used for artificial body implants in synovial joints.The thesis deals with surface-related phenomena and bulk phase behaviour that originate from the incorporation of different additives into the initial homopolymer. In the first section, the behaviour of a linear block copolymer?homopolymer blend was examined. In the second part, properties of a grafted block copolymer incorporated into the matrix film were investigated. It was found that the lubrication was enhanced by almost one order of magnitude. From the findings of the second part it is also possible to gain a general understanding of the nature of polymers that lead to lubrication-enhancing surface coatings. Further studies can lead to a transfer of this knowledge to other systems, for instance coatings for bearings in engines or computer hard discs.The main structural and depth-profiling experimental investigations were carried out using small angle neutron scattering and nuclear reaction analysis. The characterisations of the surface properties were performed mainly with optical phase interference microscopy, atomic force microscopy and contact angle measurements. To examine the friction between the sheared modified and non-modified polymer surfaces a surface force balance was used and modified according to the purposes.