Friction of thin films of rubber-like material

Abstract

What is seen as a smooth surface is, on the microscopic level, rough and irregular. Two contacting surfaces are in contact only at the peaks of their surface asperities. The friction force between the two surfaces is thought to be as that force arising from the shear strength of the randomly located islands of contact. It is seen that if a thin film of a soft material is deposited on a hard substrate, the friction force will be small. In this investigation a thin film of neoprene was deposited on an annulus machine on one face of an aluminum disk. This annulus was then pressed against a roughened glass surface and rotated concentrically in a plane parallel to the glass. Rotation was accomplished by applying a tangential weight to the disk which was subjected to a fixed normal load. The speed of rotation was varied by varying the tangential load, and the friction test was carried out in an atmosphere of dry air, the temperature of which could be varied.