Tack behavior of coating solutions II.

The tackiness of coating solutions containing high concentrations of polymers was determined using a parallel plate technique. Kinematics of the film-splitting process was also investigated using a high-speed movie camera. The results showed that the impulse required to split a liquid film of highly concentrated polymer solution (semisolid), in contrast to a dilute solution is related not to viscosity, but to the internal structures of the system. Evidence has been found that the materials that are considered to be tacky in practice, display "delayed elastic effects" and require far larger impulses than nontacky materials.