Adhesion Frequency in Interfacial Dynamics of Copolymers

This paper introduces the concept of adhesion frequency that characterizes the dynamic interaction between a polymer matrix and a solid surface. It is argued that the pressure sensitive bonding of a polymer interface occurs within a critical time scale below which no wetting is established upon contact. The adhesion frequency can be viewed as the inverse of this critical time scale. The bonding kinetics is used to model transient adhesion and take into account the growth of bonding energy with time. The mechanics of the interfacial dynamics is used to derive expressions for the adhesion frequency when inertial, viscous or elastic effects dominate the surface deformation. Transient adhesion effects are also investigated experimentally using non-axisymmetric rotating bits and commercially-available copolymer adhesives. The rotating bits induce an oscillatory motion on the polymer surface. Experiments are conducted with the rotating bits spinning at a wide range of speeds making it possible to obtain the dynamic response of the polymer interface as well as to measure the adhesion frequency for the tested polymers.