Interaction of Surface Energy Components between Solid and Liquid on Wettability, and Its Application to Textile Anti-Wetting Finish

Abstract

With various options of anti-wetting finish methods, this study intends to provide basic information that can be applied in selecting a relevant anti-wetting chemical to grant protection from spreading of liquids with different surface energy profiles. With such an aim, the anti-wetting effectiveness of fluorinated coating and silane coating was investigated for liquids having different surface energy components, water (WA), methylene iodide (MI) and formamide (FA). The wetting thermodynamics was experimentally investigated by analyzing dispersive and polar component surface energies of solids and liquids. The role of surface roughness in wettability was examined for fibrous nonwoven substrates that have varied surface roughness. The presence of roughness enhanced the anti-wetting performance of the anti-wetting treated surfaces. While the effectiveness of different anti-wetting treatments was varied depending on the liquid polarities, the distinction of different treatments was less apparent for the roughened fibrous surfaces than the film surfaces. This study provides experimental validation of wetting thermodynamics and the practical interpretation of anti-wetting finishing.

Keywords: anti-wetting; contact angle; dispersive; etching; nonwoven; polar; roughness; surface energy; thermodynamics.

Figure 1

Surface energy components of solid surfaces.

Figure 2

Wettability with different surface energy surfaces. (a) cosθ with different Φ$\sqrt{{\gamma }_S}$; (b) cosθ with different ${\gamma }_S$.

Figure 3

Surface polarity influencing wetting. (a) Percentage of the polar contribution to the overall surface energy of solids; (b) Interfacial function with % polarity.

Figure 4

Contact angle of formamide (FA), actual measurement and estimation from Equation (10).

Figure 5

Spreading parameter for surface energy and wettability. (a) Plots of cosθ with spreading parameter; (b) Spreading parameter with different surface energy of the solid.

Figure 6

Scanning electron microscopy (SEM) images of surfaces. Inserts are optical microscope images with the scale bar of 1 mm.

Figure 6

Scanning electron microscopy (SEM) images of surfaces. Inserts are optical microscope images with the scale bar of 1 mm.

Figure 7

Surface roughness observed by atomic force microscopy (AFM). (a) Polyethylene terephthalate (PET) film; (b) PET spunbond fabric; (c) alkali-etched PET spunbond fabric.

Figure 8

Wettability of substrates with different surface energy and roughness profiles.