Insight into the periodicity of Schallamach waves in soft material friction

A dominant mechanism in friction of soft material interfaces is the onset and propagation of Schallamach waves. Schallamach waves are "tunnels" of air that provide relative displacement between the slider and the substrate rather than the instantaneous interfacial failure involved with stick-slip. Here, through model experiments and analysis, the authors present a fundamental relationship between the periodicity of Schallamach waves (lambda) and the ratio of interfacial adhesion (G(c)) over complex elastic modulus (E-*). This deconvolution of bulk and interfacial contributions to the friction of soft materials leads to interesting predictions that will impact material design for a wide range of applications. (c) 2006 American Institute of Physics.