Use of a Scanning‐Kelvinprobe in the Investigation of Electrochemical Reactions at the Metal/Polymer Interface

Abstract

Abstract It is possible to measure the work‐function of polymer coated materials with a Kelvin‐probe. In a humid atmosphere this work‐function is mainly given by the corrosion‐potential of the metal substrate. The use of a scanning Kelvinprobe then allows to map the corrosion potential of polymer coated material with a local resolution of approx. 20 μm and to follow the delamination of polymer coatings as well in the vicinity of defects as on metal substrates, which are contaminated at the metal/polymer interface. Simultaneously, the diffusion of oxygen can be followed with a high local resolution after a jump of the oxygen activity within the gas phase.—The same techniques are used to analyse intrinsic defects within monomolecular LB‐films. In a dry gas phase the Volta potential map corresponds to the distribution of dipole‐potentials and therefore allows to distinguish between covered and uncovered parts of the substrate, as the ordered LB‐film shows rather large dipole‐potentials. In a humid atmosphere the Volta potential map again is dominated by the corrosion potential of the substrate and therefore the delamination of the LB‐film in the vicinity of defects can be studied as well as the stability of the film on the metal substrate far away from any defect.