What Is Foam, Exactly?
INTRO: The foam itself is a product of a chemical reaction between substances. It’s composed of water, air, and – surfactants.
How the Laundry Foam Detergent Cleans
When foaming agents (surfactants) mix with air and water, they trigger a reaction known as lathering. As a byproduct, the foam itself doesn’t actually possess any cleaning power – and with that in mind, it’s easy to jump to the conclusion that foaming is not necessary for efficient washing. However, it’s not exactly true. Foam has a specific ability to adhere to surfaces, making it a significant element of the cleaning process.
Think of different surfaces, and how a drop of water behaves on them. While it might remain for a while on a horizontally placed piece of velvet, it will quickly slide from glass, especially if it’s vertical. The science behind such behavior is called surface tension. It’s what gives a water droplet its shape, and determines its interaction with other surfaces.
In order to clean the stains, water (and detergent formula) needs to be able to penetrate the surface – and to achieve that, it needs surface tension reduced. And here we get to the role of surface-active agents, shortly: surfactants.
Surfactants create foam, and foam helps the formula react with surfaces long enough to penetrate into the dirt, grease, and other stains. Prolonged exposure, therefore, means more efficient detergent performance and cleaner clothes as a result.
Foaming Laundry Detergent Formulas
One thing that distinguishes laundry detergents, and cleaning products in general, is how they are made. Cleaners can be produced in super-simple ways, even comprising one single chemical targeting a particular soil type. That practice is commonly known as “commodity cleaners.” On the other hand, modern detergent formulas are typically blends of various chemical ingredients, each with its own designated role, blended to be more efficient together.
Laundry detergent formulas are mainly based on four fundamental elements: builders, carriers, hydrotropes, and surfactants. Builders are the roots of the formula, and the carrier is a solvent – typically found in liquid laundry detergents, can be even water. Hydrotropes serve to keep all elements stable together. And finally, surfactants create foam that traps the soil.
With some good old rubbing included, these elements unitedly create a series of actions needed to remove soils. In order to eliminate unwanted stains from fabrics surfaces, they employ techniques such as emulsifying, separating, lifting, isolating, and finally decomposing different types of soils. The efficiency of all these actions is dependent on the detergent type, which is determined by the type of surfactants used in the formula.
Yes, the foam does have a clear functional role in detergent formulas. However, producing loads if it is not a necessary factor.
What Is a Surfactant in Detergent
INTRO: Surfactant in laundry detergent is a chemical compound added to the formula to create a connection between water and oil.
One of the common questions our experts are asked is: does surfactant in detergent repel water? The answer is yes and no, in equal proportions.
Similar to magnets, surfactants feature two opposite ends. While one of its ends is tending towards the water, the other is fighting to stay away from it. The first one is called “hydrophilic end,” from the ancient Greek ὑδρο (ydro), which means water, and φίλος (philos), which means friendly/loving. The other one is known as hydrophobic, and it again has roots in Greek – φόβος (phóbos) means “fear.”
The hydrophobic end contains hydrocarbon chains that prefer oil and grease over water. And that’s the key to surfactants’ cleaning functionality.
The Role of Surfactants in Laundry Detergents
In order to escape from the water, the hydrophobic end forms a spherical shape, leaving the hydrophilic water-loving end like a shell on the outside. This shape is known as a “micelle,” the word probably familiar to you due to the detergent surfactants in cosmetics and the popularity of face cleansers using similar technology. Micelles are what catch the dirt so that it can be removed. The trick? As both the soil and the micelle interior are hydrophobic, they connect together and remain cozy inside the hydrophilic shell.
Once the soil is loosened or completely removed from the treated surface, it can be rinsed away with the help of the hydrophilic end of the surfactant.
What Surfactants Are Used in Laundry Detergents
Surfactants are categorized according to the electrical charging of their hydrophilic end.
Negative charging results in anionic surfactants. This type produces a lot of cleaning foam, with an abundance of molecules ready to pick and encase soils inside their micelles. Anionic laundry detergents are suitable for a broad range of soils. For that reason, their common forms – SLES, sodium lauryl sulfate, alpha olefin sulfonate – are most frequently used in soaps and foam detergents. However, hard water conditions may decrease their efficiency, making other options preferable.
Positive charging creates cationic surfactants, ideal for use in anti-static formulas such as fabric softeners, or as antimicrobial agents in disinfectants. Due to the natural charging interaction, cationic and anionic (negatively charged) surfactants can’t be mixed, as they would render the foam detergent inactive. Cationic surfactants may, however, be added to the same formula as neutrally charged nonionic surfactants. Alkyl ammonium chloride is the typical form of cationic surfactant in laundry detergents.
Neutral charging produces nonionic surfactants, meaning there is no charge on their hydrophilic end. This type is better than anionic in emulsifying oils and organic soils. The two are frequently found as a surfactant blend in detergents boasting more efficient formulas such as multi-purpose or dual-action.
Nonionic surfactants are a common ingredient in non-foaming or low-foaming detergents, due to their unique property known as “the cloud point.” A nonionic surfactant separates from the rest of the formula at a specific temperature, making it appear cloudy – hence the name. That temperature point can be defined by the manufacturer by manipulating the surfactant’s hydrophobic/hydrophilic ratio. The cloud point sets the conditions for optimal detergency, making the nonionic detergent efficient without excessive foam micelles.
Common nonionic surfactants found in laundry detergents are cocamide diethanolamine (cocamide DEA) and fatty alcohol ethoxylates.
Surfactants are crucial in cleaning products, with multiple roles as wetting agents, emulsifiers, and dispersants. But most of all, they change how water behaves – by reducing the surface tension, they allow it to spread out and penetrate every inch that needs to be cleaned. And by trapping the dirt, they help the formula eliminate it from the treated surface.
What Happens When High Foaming Becomes Too High
INTRO: Too much foam can be a hassle and even lead to poor washing results. You may now wonder why, considering that more foam means more active micelles. The answer is that creating micelles is not the foam’s only property. Foam is also slippery; therefore, an abundance of suds prevents rubbing, which is another element of a proper laundry washing process.
One more issue that comes with over-foaming is wasting. Excessive suds are harder to rinse, hence requiring more time, water, and electric energy. And finally, too many suds can interrupt the washing process, causing the machine to stop pumping water out or even blocking the system.
There are, of course, some components that manufacturers use to control the suds while keeping the process as efficient as possible. Suds control agents, for instance, prevent over-foaming. At the same time, components such as anti-redeposition agents prevent soils from settling back to the cleaned fabrics. That’s why using quality and powerful laundry detergents rarely ends up in side effects and problems.
How to Prevent High Foaming Issues
First of all, proper dosing is the best thing you can do to prevent excessive foaming. Most detergent packages feature instructions regarding the loads, types of soil, and adequate doses for each. Alternatively, it’s also possible to use detergent pods and avoid measuring altogether.
Another factor to consider is the hardness of the water. Soft water requires slightly less laundry detergent than hard water, for the same load. Anti-lime-scale products and water softening systems can also play a role here.
A laundry softener can serve as the first aid, particularly if it contains cationic surfactants. As we have stated earlier in this article, positively and negatively charged surfactants can’t work together. If the laundry detergent is excessively foaming, it’s probably loaded with an anionic surfactant. Therefore, adding the softener will reduce its foaming power.
When to Use High Foaming Detergent
Generally speaking, low foaming detergents are better suited for ultrasonic and fully automated laundry machines. The convenience of such washing is high because the programs mostly take care of the whole process. In other cases, however, high foaming laundry detergents are a better solution. That particularly applies to older types of machines and manual washing. Foam micelles require less physical labor and deliver more time-efficient results.
Proper dosing and familiarity with the specific conditions are the keys to preventing issues connected with excessive foaming. It’s essential to follow the manufacturer’s instructions featured on the package. If the problems occur, a dose of fabric softener may be a convenient first-aid solution.
The bottom line
So, finally, does more foam mean better cleaning results? No, not really. A washer overloaded with foam, for instance, will only bring you problems. The amount of foam doesn’t necessarily affect the detergent’s cleaning ability – for as long as it’s present enough to make the reaction happen. This further means that most detergents DO need some foam in order to do an efficient job.
