Hoping you could help us on this!
Reply: Surface energy measurement does not give any indication of expected adhesion. Surface energy can give an indication of how well a coating will wet the surface and can give an indication of a surface being contaminated, but not of adhesion.
The surface energy of a clean surface is likely to be higher than the surface energy of a contaminated surface. So treating the surface is often cleaning the surface to remove or stabilise a surface contaminant. If the low energy contaminant is removed the surface energy will rise back to the level of a clean surface.
Some surface treatments can be over done and the surface broken up in to very short chain length polymer fragments which are no longer bonded into the bulk polymer and so whilst the surface energy measures the same as a clean surface the adhesion is poor.
Hence it is important to consider the adhesion at each interface. If there is metal transfer it would indicate that the adhesion of the metal to the substrate is not good enough. A simple measurement of the surface energy of the substrate will not tell you why this is other than telling you if the surface is contaminated. Any treatment of the surface needs to be optimised for the particular film that is being treated. Any surface treatment process needs to be customised for the type of substrate and even the age of the substrate. Polymers are hard to polymerise to 100% and so there is an amount of unpolymerised monomer or oligomer that s left in the film following manufacture and this oligomer can migrate to the surface. Depending on the time and temperature will depend on how much is present on the surface. So the newer the film the less contamination is likely to be present and so the treatment can be less than for an older film where the contamination level has had time to build up.
I would look back at the history of your film to see when it was made, treated and metallised and compare this to films where there was no metal transfer. If this is not possible then I would suggest that you look at optimising the metal adhesion and that may require optimising any film pretreatment.
I hope this helps.