B.N. Altay, M. Sta, P.D. Fleming, N.R. Demarquette, S.G. Cloutier
Rochester Institute of Technology,
Keywords: surface energy, substrate, printed electronics, sessile drop, surface science
Summary:Estimating surface energy (SE) of substrates is of great interest in many fields, including surface chemistry, material characterization, coatings and printed and flexible electronics. There are numerous theoretical and semi-empirical models and liquids used to estimate SE of substrates. The widely-known Owens-Wendt (OW) model makes use of surface tension of at least two liquids with known dispersive and polar components and their contact angles on a given substrate to estimate the SE. Using different SE theories and test liquids may result in significantly different SE value for the same substrate. An alternative method is exemplified in this study to demonstrate obtaining equivalent SE results that is evidenced by a general thermodynamic inequality relating the 3 interfacial tensions in a 3-phase equilibrium system. The alternative method always satisfies this inequality; however, the OW method seldom, if ever, conforms to the inequality and even then, the degree of satisfaction is not significant.