In this project photochemical methods will be developed in order to attach functional groups onto the surface of technically important polymers. These methods have the advantage that projection techniques allow illumination - and thus modification - of selected areas of the polymer surface. This is a distinct contrast to other techniques of surface modification (e.g., corona discharges, gas flames or plasmas). MALDI-TOF MS will be employed for the characterisation of the modified polymer surfaces. This is essential in order to determine how experimental parameters of the photomodification methods have to be varied to achieve a controlled and well defined composition of polymer surfaces. In a second step, chemical transformation reactions will be used to convert the photochemically introduced functional groups. Again MALDI-TOF MS results will be used for optimisation of the reaction conditions towards increased uniformity and selectivity. All investigations will be assisted by other analytical techniques (e.g., FTIR, SEC, XPS, EDX). The experiments will be focused towards the introduction of acidic (e.g., -SO3H, -COOH), basic (-NH2) as well as neutral (-CN, -SO2NHR) groups. The controlled introduction of such functional groups is a key for numerous applications. The MALDI-TOF MS investigations are essential for both development and application of the surface modification methods under consideration.