Assessment and Interpretation of Surface Wettability Based on Sessile Droplet Contact Angle Measurement: Challenges and Opportunities. Issue 18 (2nd August 2019)

• Record Type: Journal Article
• Authors: Kung, Chun Haow; Sow, Pradeep Kumar; Zahiri, Beniamin; Mérida, Walter
• Is Part Of: Advanced materials interfaces. Volume 6:Issue 18(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-02
• Subjects: Cassie–Baxter -- contact angle -- superhydrophobicity -- Wenzel -- wettability; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201900839
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Surface wettability, a property that governs the interaction between the solid and liquid phases, is central in various biological systems and technological applications. A typical approach to assess the wetting interaction is based on the sessile droplet contact angle. Despite its experimental simplicity, caution is required in the measurement and interpretation of the sessile contact angle as a wettability metric. In this work, the major challenges related to the use of the sessile droplet contact angle for characterizing surface wetting behavior are reviewed. The complexity of interpreting surface wettability using the contact angle value arising from the following factors is discussed: the role of solid–liquid interfacial area and three‐phase contact line, the existence of multiple metastable states with a range of contact angle values, and the droplet size dependence of contact angles. An overview of the emerging alternative wetting evaluation techniques and parameters that can complement the sessile contact angle measurement is outlined. Abstract : The challenges in using the sessile contact angle (CA) as a wettability metric are reviewed. Three main issues complicating the CA interpretation are discussed: the role of the interfacial area and contact line, the multiplicity of CA, and droplet size dependence of CA. Recent advances in developments of new wetting characterization techniques complementary to the CA method are highlighted.