Wetting and Wicking

Abstract

The fundamentals of wetting and wicking are reviewed. Wetting is the displacement of a fiber-air interface with a fiber-liquid interface. Wicking is the spontaneous flow of a liquid in a porous substrate, driven by capillary forces. Because capillary forces are caused by wetting, wicking is a result of spontaneous wetting in a capillary system. Fiber wettability is therefore a prerequisite for the occurrence of wicking. The inter action of liquids with textile fabrics may involve one or several physical phenomena. On basis of the relative amount of liquid involved and the mode of the liquid-fabric contact, the wicking processes can be divided into two groups: wicking from an infinite liquid reservoir (immersion, transplanar wicking, and longitudinal wicking), and wicking from a finite (limited) liquid reservoir (a single drop wicking into a fabric). According to fiber-liquid interactions, each of the four wicking processes can be divided into four categories: capillary penetration only, simultaneous capillary penetration and imbibition by the fibers (diffusion of the liquid into the interior of the fibers), capillary penetration and adsorption of a surfactant on fibers, and simultaneous cap illary penetration, imbibition by the fibers, and adsorption of a surfactant on fibers. When designing tests to simulate liquid-textile interactions of a practical process, it is essential to understand the primary processes involved and their kinetics.

Thermophysiological Wear Comfort of Clothing: An Overview

“…This capillary penetration of a liquid may occur from an infinite (unlimited) or a finite (limited) reservoir [56]. The different forms of wicking from an infinite reservoir are transplanar or transverse wicking, in-plane wicking and vertical or longitudinal wicking.…”

“…In this process the fibre-air interface is replaced with a fibre-liquid interface. The forces in equilibrium at a solid-liquid boundary are commonly described by the Young-Dupre equation, given below [35]:…”

Enhancing the surface properties of linen by non-thermal atmospheric air-plasma treatment

“…Water and α-bromonaphthalene were used as high-energy liquids. Wicking rate was measured and the apparent (effective) pore radius (R), the dynamic contact angle, the dispersion and polar components of the solid surface and the free energy of the fabric (γ s total ) were calculated [14][15]. At least eight wicking measurements were made for each fabric in warp direction and the averaged wicking time was used for the calculations.…”

Analysis of Steam Formation and Migration in Firefighters’ Protective Clothing Using X-Ray Radiography

“…Therefore, moisture was also present in the neighbouring layers of the wet layer at the beginning of the X-ray radiography measurement. However, it has been shown that wicking can only occur when a certain threshold value of moisture content in the wet layer is exceeded [17,18,19]. Thus, with UW 0.6 (i.e., 0.6 g of water initially located in UW) this threshold value was probably not reached and, therefore, no moisture wicked to the liner.…”