Why are there towels that don’t dry?

There are towels that dry better than others. Is there a scientific reason it explains? Here, some brush strokes. The cotton towel consists of fibers that form capillaries. If we place them relaxed and next to each other, a surface is much larger than the towel. Therefore, when we dry, the water is deposited on the surface of our body by a very large absorption surface, the inner and outside of all capillaries of the towel. In this process, the most important component of cotton, cellulose, which has a large capacity to attract water molecules, has a fundamental influence. Moreover, the hydrophilic and capillarity properties of the capillaries also suck water. That is why it is not necessary to rub to dry. Simply support the towel in our wet body so that the suction and absorption of water occur.

One way to check these characteristics is to see what happens with a new (brand new) and with another that has been washed several times. While the one used well, the new dry very little. That is because the new one was treated with a conditioner that makes its surface more hydrophobic and is therefore less able to absorb water. This occurs to a lesser extent when we introduce softener in the washing machine. The towel is softer and more pleasant but loses efficiency in its function of drying the wet body.

To look for new softeners who do not reduce the efficiency of the towel, it is necessary to understand why the towels are washed without them and are roughly rough in the air. Very recently, with the help of experimental techniques that provide microscopic information on the subject, it was possible to know what the reason is for that stiffness and roughness.

The first thing that was proven was that, although it seems dry, a certain amount of water is stored in the towel fibers. We don’t notice it, because when we play it, it doesn’t get wet.

This always happens, even in environments with a very small relative humidity. This water that is linked to the surface of the fibers produces, due to adhesion, stiffness and therefore the towel is rough. Something similar to the effect of a varnish or glue. The image shows schematic adhesion points.

Moreover, an unexpected result was found. Water shows a special link called ‘Hydrogen Bridge’. In the case of the towel, the water that is linked to its fibers shows a unique state of this link, other than that of normal water.

Two experiments support the earlier interpretation about the stiffness in the crops towels without a softener and air -dry. It consists of the mechanical breaking of hydrogen bonds, something that takes place in a drum dryer. The second, when extracting the linked water, placing the towel in a housing in which it can be empty. In both cases the towel is soft touch.