Scientists investigate mystery of telephone cord buckles
(PhysOrg.com) -- Ranging in thickness from a few nanometers to several micrometers, thin films and coatings play a role in a wide variety of applications. The reflective metal layer on a mirror, the coatings on low-emissivity or colored windows, and the thin silicon layers on thin-film solar cells all consist of thin films. When thin films are compressed with enough force, they can buckle and delaminate under compressive stress. Starting from defects, the buckles propagate, delaminating the film substrate interface on their way. Buckles can be straight, circular, or even take the three-dimensional coiled shape of a telephone cord. Although researchers have studied telephone cord buckling in thin films for decades, they still don't fully understand their propagation mechanisms. A new study now sheds some light on this area.