Interface failure and adhesion measured by focused ion beam cutting of metal–polymer interfaces

Abstract

New developments in flexible electronics require metal films to adhere to polymer substrates. Measuring the interfacial adhesion of these systems is challenging, requiring the formulation of new techniques and models. A strategy to measure the adhesion of Cr–polyethylene terephthalate (PET) interfaces using tensile straining and buckle formation is presented in this article. Focused ion beam cross-sectioning of the buckles reveals that the polymer substrate can locally fail, which may lead to an overestimate of adhesion. Cr–PET adhesion energy of 9.4 ± 1.6 J/m² is determined with the present approach.

Keywords:

• thin films
• buckling
• atomic force microscopy
• focused ion beam
• adhesion energy

Acknowledgements

Funding for this research has been provided by the FWF Lise Meitner Fellowship (project no. M1041-N14) and FWF Einzelprojekt P22640-N20. Fruitful discussions with F.D. Fischer are also acknowledged.