Contact mechanics, adhesion and friction of rubber materials

In this chapter we discuss contact mechanics, adhesion and friction of relatively soft materials (rubber materials), which are relevant in many engineering applications from the micro-and nanoscales up to the macro-scale. We review the main theories of contact mechanics and discuss the main results, advantages and drawbacks of such theories. The influence of surface roughness on the contact mechanics of solids is discussed as well as the origin of the direct proportionality between the area of real contact and the applied load. We also discuss the origin of friction in viscoelastic materials and show that the bulk viscoelasticity, the adhesion hysteresis and the viscoelastic crack propagation all give an important contribution to friction.