New equations of wetting

ABSTRACT

The contact angle and static equilibrium of the triple contact line of a sessile droplet are investigated. New wetting equations are derived by minimising the total potential energy of the droplet. These differ from the previous equations of Young, Wenzel and Cassie-Baxter. The new equations show that the contact angle is influenced by the edge energy of the triple contact line and the local roughness at the triple contact line, and is independent of the interfacial area within the triple contact line. Through these new equations, answers have been obtained to existing problems that cannot be explained by the above-mentioned theories.

KEYWORDS:

• Wetting triple contact line
• contact angle
• Young's equation
• interfacial energy

Acknowledgments

The support of the National Nature Science Foundation of China through the Grant Nos 11172130 and 11672129 is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Zaixing Huang http://orcid.org/0000-0003-2440-757X

Additional information

Funding

The support of the National Nature Science Foundation of China [grant nos 11172130 and 11672129] is gratefully acknowledged.