Universal Scaling Behavior of the Tackiness of Polymer Melts

This presentation describes the measurement of stickiness or tackiness, as measured by the peak force to pull off a cylindrical probe from neat polyisoprene melts, the latter of varying materials and surface roughness, over a range of separation speeds. The polymers were either linear or star-branched, with the molecular weights of the former ranging from 84 to 476 kg/mol and of the latter from 609 to 1130 kg/mol. Dynamic mechanic measurements of the polymers showed normal and classic behavior to this well-characterized system. We find that when the pulling speed (V_s) is greater than a critical speed (V_c), the maximum tack force (F_max) can be generally described by the following scaling relationships: F_max ~ V_s^1/3 and F_max ~ t_max^-1/2, where t_max the time when the maximum force is reached in the force-time profile. Remarkably, this scaling behavior of the tackiness appears to be universal as it is independent of the adhered surface, the molecular weight distribution, and the linear or branched chain architecture of the polymer melt. We connect these relations to the physics whereby the tack is controlled by the crack propagation along the interface.