Tentative Correlation between Contact Angle Hysteresis and Adhesive Performance

✍ Scribed by S. Bistac; P. Kunemann; J. Schultz

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 64 KB
• Volume: 201
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1998.5427

✦ Synopsis

NOTE Tentative Correlation between Contact Angle Hysteresis and Adhesive Performance

is the measure of the advancing u A and receding u R contact angles of a liquid drop (1 mL) deposited on the EVA film (Kruss apparatus). The

In this work, the surface properties and adhesive performances second method is measurement of the advancing angle (wetting) and recedof three ethylene vinylacetate copolymers are investigated. A tening angle (dewetting) of a polymer film immersed in a liquid using the tative correlation between the evolution of the contact angle hystensiometry or dynamic contact angle technique at a speed equal to 13 mm/ teresis and the variation of the adherence force is proposed. The min (DCA apparatus from Cahn). The adhesive properties of the PET/ wettability measurements results indicate that one of the EVA EVA/PET assemblies (2 cm width samples) are studied using a peel test possesses a very low surface energy, explained by the presence on (peel angle Å 180Њ) at a speed equal to 100 mm/min on an MTS tensile the surface of an additive. This copolymer exhibits, however, the machine. greater contact angle hysteresis and the higher adherence level. This behavior can be explained by the probable merging of some RESULTS AND DISCUSSION polymer chains on the surface, through the contamination layer, and by a possible increase of the polymer energy dissipation prop-Table 1 presents the surface energy of the EVA films. The dispersive erties induced by the presence of the additive molecules. ᭧ 1998 component g D s and polar (or nondispersive) component g P s of the surface Academic Press energy g s are calculated using tricresyl phosphate (TCP) and diiodomethane Key Words: contact angle hysteresis; adherence; surface energy; for g D s and water for g P s (10). It clearly appears that the surface energies ethylene copolymers.

of the different EVA are not identical, despite the fact that all the EVA are theoretically chemically identical (same VA content). Indeed, the surface energy of EVA C is significantly lower compared to the other copolymers, with a polar component close to zero. A plausible explanation is the presence, in EVA C, of an additive (process agent), present in the bulk but