How Do You Get a White Vest?

The need and the necessity for doing the laundry are as old as mankind itself.

Since man has learnt to improve the body’s covering with furs, animal skins and plant material, the necessity to free those ”clothes“ - for whatever reasons - from clinging dirt has existed.

The most important procedure for as long as anyone can remember is treating the laundry with water and mechanical forces. It was also discovered early, that adding certain additives increases the washing power of the water. The oldest additives with the ability to increase the washing power are soap and soda (Na₂CO₃).

But What Is Contained in Today’s Detergents?

The most important components are:

· Tensides

· Builders

· Bleaching agents

· Optical brighteners

They are surfactant substances, and they considerably lower the high surface tension of the water.

With those substances, it is easier to dissolve hydrophobic soiling in water.
In aqueous solutions, tensides usually don’t occur as single molecules, but as micelles. At the interfaces, the tenside molecules line up.

How Does Washing Work, Now?

As a result of its low surface tension, the soapy water can now penetrate into the spaces between the fibres, dissolve the dirt there, adsorb it orientated, and keep it hovering in the soapsuds.

And What Are the Other Components for?

They have different functions:

Builders have the main task to eliminate the disturbing hardness of the water. In addition, they aid the washing process.

In former times, soda carried out this task. Today, zeolites and combinations of phyllosilicates and citrates are used.

Since the beginning of the century, sodium perborate serves as bleaching agent. In aqueous solutions it gives off oxygen, which has a bleaching effect.

In order to cope with the demands of the costumers for even whiter laundry, optical brighteners are used.

Formerly, laundry blue was used for this purpose, since a white with a blue cast appears whiter than the yellowish white you get through washing and bleaching.

Under a UV lamp, you can see the increased blue proportion in the reflected light as a bluish fluorescence.

Today, optical brighteners are substances which are able to transform the invisible ultraviolet light contained in the light shining on the surface into visible light.

Subsequently, the laundry shines brighter by this light.
The effect of optical brighteners is only an aesthetic effect.

As you can see, doing the laundry is a very complex process, as a number of factors have to be taken into account.

Whereas the removal of the dirt has to be powerful, the fabrics require a very mild treatment. Therefore, the washing process is always a compromise.