Morphological evolutions of iron films on PDMS substrates under uniaxial compression/tension

Abstract

We report on the morphological evolutions of iron films sputtering deposited on elastic polydimethylsiloxane (PDMS) substrates under uniaxial compression/tension. The experiment shows that the as-prepared film (no external strain) spontaneously forms cracks and wrinkles due to the residual thermal stresses stored up during/after the film deposition. The external uniaxial compression can generate delaminated buckles perpendicular to the loading direction (transverse direction) and new cracks in the loading direction (longitudinal direction). Subsequent reloading and further straining result in the formation of transverse cracks and longitudinal buckles. It is found that there exists a significant coupling effect between the cracking and buckling patterns during the compression/tension process. The morphological evolution behaviours and underlying physical mechanisms are discussed and analysed in depth in this paper.

Keywords:

• Thin film
• polymer substrate
• buckling
• cracking
• uniaxial loading

Acknowledgements

The authors thank Hong Zhou and Yong-Ju Zhang for useful discussions and technical assistance.