yarn wicking instrument

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INTRODUCTION

Wicking is the spontaneous flow of a liquid in a porous substrate, driven by capillary forces. Thus the term ‘wicking’ refers to transfer of moisture/liquid by a porous material or in a network of fibre assembly through capillary action, from one point to another in any given direction. Wicking can happen through a cord or strand of loosely woven, twisted, or braided fibers, or in any porous structured materials with the sufficient pore size with the intrinsic characteristics of the material itself. In general, wicking takes place when a liquid travels along the surface of the fibre but is not absorbed into the fibre.


Wicking of Fabric
Wicking fabrics can be defined as the transfer of moisture from one point to the other through capillary action. Wicking of fabrics is of commercial importance for providing comfort for the wearer, particularly in regular apparel and recent technical fabrics to draw moisture away from the body. Such fabrics are made of high-tech polyester, which, unlike cotton, absorbs very little water. Cotton will absorb 7% of its weight in water, polyester only 0.4%. Cotton will therefore hang onto your sweat, making your garment heavy and unpleasantly clammy. Wicking polyester has a special cross-section and a large surface area, which picks up moisture and carries it away from your body, spreading it out, to evaporate easily on the outside of the fabric


Wicking of Yarn
There are many wicking test methods and instruments available for testing the wickability of fabric. However only very few studies are reported on yarn wicking. This may be important in certain cases where the filament may be used for wicking or nonwicking applications, and for some special applications where quick dry applications such as sportswear, special prints that needs to have sharp and clear edges, all such applications requires deep consideration of wicking characteristics of filament.



Factors that Influence Wicking
Capillary Pressure
Capillary pressure is the main force responsible for the movement of moisture along or through a fabric, where the force of the surface tension between the liquid and the walls of a narrow gap or pore overcome the forces between the molecules of the liquid, moving it into empty gaps until the forces even out. As the capillary pressure increases wickability increases.

Permeability
Permeability is the measure of a fabric's ability to transport moisture through itself, and is determined by a combination of sizes of spaces within it and the connections between the spaces. As the permeability increases wickability increases.

Surface Tension
It is a property of liquids arising from unbalanced molecular cohesive forces at or near the surface, as a result of which the surface tends to contract and has properties resembling those of a stretched elastic membrane. As the surface tension increases wickability increases.

Adhesion
The physical attraction or joining of two substances, especially the macroscopically observable attraction of dissimilar substances is known as adhesion. As it increases wickability will increase.

Cohesion
It is the intermolecular attraction by which the elements of a body are held together. As it increases, wickability increases.
Hydrophilic Nature
Having an affinity for water; readily absorbing or dissolving in water, with increase in hydrophilic nature wickability increases rapidly.