Nanotopography and morphology along metal-polymer interfaces
|PhD ceremony:||Mr E.T. Faber|
|When:||December 19, 2014|
|Supervisor:||prof. dr. J.T.M. (Jeff) de Hosson|
|Co-supervisor:||Prof. W.H. Vellinga|
|Where:||Academy building RUG|
|Faculty:||Science and Engineering|
Steel cans used for liquid and/or food packaging are typically protected from corrosion using a thin tin layer, and as an alternative to tin poly(ethylene terephthalate) is being explored. Adhesion and de-adhesion at the polymer/metal interface are expected to be crucial for the performance of such coatings.
In this thesis the adhesion is studied on a small scale. In order to explain the adhesion behavior, the evolving structure and roughness of the steel are studied in several ways. A new method is demonstrated by which the surface topography of samples can be determined from multiple microscope images, and this method is used to quantify the movement of grains and glide steps in three dimensions.
From cross-sections produced with an ion beam certain adhesion phenomena are observed, including the mechanism by which most likely the de-adhesion is initiated: dislocation slip causes steps at the interface, which strain the polymer very locally. A study of the texture and structure of the steel from the can indicates that the interface roughening is explained by grain orientations and by slip.