A Look at Surfactant Chemistry
To understand how green laundry detergents work, you must first answer the question: how do detergents in work in general. You will find the answer to this question by looking at surfactants. Detergents are made up of a mixture of chemicals. Surfactants are the chemicals in the mix which are able to dissolve the dirt from the laundry surfaces. Surfactant chemistry explains how detergents really do their job.
Surfactants are molecules, which can be attracted to water-repelling substances at one end of the molecule and to water and water-loving substances at the other end. A surfactant molecule has an electrically charged (water loving) head and a electrically neutral (non-water-loving) tail which is eight to twenty carbon atoms long.
As the surfactant molecule is bopping around in the water of your washing machine it comes in contact with some oily or insoluble substance on your clothes. The tail of the surfactant molecule find itself sticking to this stuff because it is oily itself. At the same time, the water loving head of the surfactant molecule will continue to maintain a strong interaction between itself and the water molecules that are surrounding it. In this way surfactant molecules bridge the surface of a water repelling substance and the water in which the substance is immersed. The mutual attraction of the surfactant molecule to oily substances, on the one hand, and water on the other hand is what makes a surfactant molecule able to do its job in the laundry.
How do detergents work? Detergents emulsify!
In a washing machine over time, more and more surfactant molecules gather on the surface of the oil or soil on the laundry fibers as described above. Eventually so many surfactant molecules gather on the surface of the oil or soil that they are able to actually surround that bit of oil or dirt and roll it up into globules. The end result of this is that the oily globules are lifted up off from the laundry surface and out into the motion of the wash water. Once suspended in this manner the oil and dirt globules remain floating free surrounded as it is (on the outside) by a layer of water loving surfactant heads. In this way oily substances effectively become emulsified by surfactant molecules, and removed from the laundry that you are trying to clean.
Fine Tuning the Process of How Detergent Works in Your Washing Machine
This whole chemical interplay of detergent, dirt and water needs just the right mix of water and quantity and nature of surfactant molecule to take place appreciably. If there are too few surfactant molecules, and too little energy in the water, the surfactants will not be able to surround and carry away oil and dirt globules as described. However, too many surfactant molecules will cause a problem as well because they will stick to every fiber present and copious rinsing will be required to really rid the laundry of the thus resultant surfactant layer.
Surfactant activity is also affected by water hardness (mineral content of the wash water). Higher mineral ion content of wash water impacts the activities and availability of the surfactant molecules. The more minerals there are in the wash water, the less cleaning the surfactant molecules can actually do because mineral ions in the water react with the water loving head of the surfactant causing the molecule to fall out of solution thus rendering it completely unavailable as a surfactant.
There are different ways to address the problems that arise in a washing environment due to water hardness. More substances must be brought into the detergent mix in order to deal with wash water mineral content. The detergent Industry has turned to the use of powerful, and environmentally complex molecules to eliminate the impact of water hardness upon surfactant cleaning abilities. these molecules are call hardness sequesterants or water softeners. The new synthetic water softeners should be regarded with caution. Synthetic compounds time and again turn out to carry serious environmental impacts.
At any rate, there are other, more simple ways of addressing these laundry cleaning issues. Green laundry detergents will make use of these simpler solutions in their formulations. Washing Soda is the traditional hardness sequesterant. Green laundry detergents usually include washing soda in the mixture. This sequesterant does not have extremely serious or long term health and environmental impacts.
More Details on Surfactants
This post is part of the series: Green Laundry Detergents
- Green Laundry Detergents: First Understand What is in Laundry Detergents
- Green Laundry Detergents – Understanding Surfactants, The Detergent’s Mover and Groover
- Green Laundry: Water Hardness and What Your Detergent is Up Against
- Green Laundry Detergents Versus Regular Detergents & Their Tag-Alongs
- “Green Laundry Detergents” that really are “Green”