Surface functionalization of polymeric, organic and inorganic materials

The surface modifation of polymers plays an important part in the enhancement of the performance of basic polymers and offers new approaches toward the development of tailored materials for specific applications. Whilst the activation of polymer surfaces by corona and plasma treatments is a well established technique (and is performed in our labs as a standard method), the functionalization of functional polymer surfaces with (nano)particles is pursued on a scientific level.  

Intrinsically photoreactive polymers are mainly applied as photoresists which rely on the alteration of solubility upon UV irradiation. However, by using specific photoreactive groups, which undergo photoinduced isomerizations, also the surface properties (e.g. polarity and chemical reactivity) can be modulated. This is e.g. realized with photosensitive co-polymers of styrene and 4-vinylbenzyl thiocyanate, which are employed for the immobilisation of aminofunctionalized silica nanoparticles (SiO2-NP) at the polymer surface. Upon UV irradiation of the co-polymer, isothiocyanate (NCS) groups are generated by a photo-isomerisation reaction of the thiocyanate (SCN) groups. The silica nanoparticles are selectively immobilised in irradiated areas by the formation of thiourea links. By using photolithographic methods, patterned silica structures (μm scale) were produced on the polymer surface. The SiO2-NP covered surfaces are of potential interest to generate protective surface layers and to carry out further functionalization reactions of the immobilized SiO2-NP particles.