Telephone cord buckles—A relation between wavelength and adhesion. (February 2015)

• Record Type: Journal Article
• Authors: Faou, Jean-Yvon; Parry, Guillaume; Grachev, Sergey; Barthel, Etienne
• Is Part Of: Journal of the mechanics and physics of solids. Volume 75(2015:Feb.)
• Page Start: 93
• Page End: 103
• Publication Date: 2015-02
• Subjects: Thin films -- Adhesion -- Buckling -- Delamination -- Finite elements method -- Cohesive zone model -- Adhesion testing -- Residual stresses; Mechanics, Applied -- Periodicals; Solids -- Periodicals; Mechanics -- Periodicals; Mécanique appliquée -- Périodiques; Solides -- Périodiques; Mechanics, Applied; Solids; Periodicals; 531.05
• DOI: 10.1016/j.jmps.2014.11.008
• Languages: English
• ISSNs: 0022-5096

Abstract

Abstract: Thin films with low adhesion and large residual stresses may buckle. The resulting morphologies are varied, but one of the most commonly observed is an intriguing oscillating pattern – the so-called "telephone cord" – which has been extensively investigated in the recent years. We have studied the kinematics of formation of telephone cords using a geometrically non-linear plate model and mode dependent interfacial toughness, captured via a cohesive zone. Through extensive Finite Element Simulations, we have demonstrated a simple, non-trivial relation between telephone cord wavelength and interfacial toughness. To validate this prediction, highly stressed Mo thin films were deposited on Si wafers, with a well defined interface and very reproducible adhesion. Studying the morphology of the resulting buckles for different film thicknesses and stresses, we observed a trend which was fully consistent with our simulation results. From the data fit, an adhesion energy of 0.58±0.04 J m −2 for the SiO2 /Ag interface was inferred, which compares well with literature estimates.