CONTROLLED MORPHOLOGICAL EVOLUTIONS OF SILVER FILMS ON COMPLIANT SUBSTRATES BY TUNING MECHANICAL STRAIN

Abstract

Controlled surface morphologies of stiff films on compliant substrates possess a variety of applications, ranging from stretchable electronics, surface engineering to biomimics. Here, we report on the morphological evolutions of silver films deposited on prestretched compliant PDMS substrates by tuning the film strain in unloading, reloading and further stretching processes. It is found that the silver films generate transverse (perpendicular to the loading direction) wrinkles and longitudinal (parallel to the loading direction) cracks during the unloading process. On the contrary, longitudinal wrinkles and transverse cracks can be observed during the further stretching process. The morphological characteristics, evolution behaviors and mechanical mechanisms of the crack and wrinkle patterns are investigated in detail. The report in this work could promote a better understanding of the morphological evolutions of stiff films on compliant substrates by tuning the mechanical strain.