Functionalisation of surfaces by integration of nanocapsules
Martina Cybik, University of Duisburg-Essen, Essen, GermanyChristian Mayer, University of Duisburg-Essen, Essen, Germany
Functional reagents are enclosed into polymer nanocapsules with diameters around 300 nm. These are incorporated into metallic or paint coatings to establish functionalities like local lubrication or corrosion protection. Two approches are being applied:
The integration of the nanocapsules into metallic surfaces is done by a modified Ni-Watts galvanic process. In case of encapsulated lubrication agents, the new functionality is proven by tribological analysis. Due to the fact that the standard polycyanoacrylate nanocapsules show a negative zeta potential, the electro-phoretic migration of these particles during the electroplating step initially directs to the wrong (positive) electrode. Thus positive zeta potentials which can be achieved by cationic polymers (e.g. Chitosan) are required.
Nanocapsules filled with a high concentration of corrosion inhibitor or reactive resin components are dispersed into a waterbased paint to get a stable system. In the paint layer, they are opened by local damage. The scratches are partially sealed with reactive resin and corrosion is stopped by corrosion inhibitor. The anti-corrosive function of the layer has been proven by potentiometry.