What is fabric softener and how does it work?
Fabric softener is a laundry additive designed to soften and condition fabrics (you’ll also hear it called fabric conditioner).
The short answer to “How does fabric softener work?” is: it coats the fibres of the fabric, reducing friction and giving them a smoother, softer texture. But if you’re interested in the science behind fabric softener, let’s take a deeper dive!
Both laundry detergent and fabric softener contain something called surfactants, short for surface-active agents. Laundry detergents usually have surfactants that have a negative electrical charge, called anionic surfactants. So during the wash cycle, they give the fibres of your fabrics a negative charge.
On the other hand, fabric softeners contain cationic surfactants, which are positively charged. As you might remember from chemistry class, negatively charged and positively charged objects are attracted to each other. So when your fabric softener is added to the cycle, negatively charged fabric fibres attract and bind with the positively charged surfactants.
The tiny molecules that make up cationic surfactants have a head and a tail. The tails are hydrophobic, which means they’re repelled by water, and the heads are hydrophilic, which means they’re attracted to water. So in the wet washing machine, these molecules attach to the fabrics tail-first, leaving the heads to face outwards towards the wet environment.
Together, the heads create a smooth film over the fabric fibres, which acts as a lubricant to reduce friction between the fibres. Not only does this make the fabric feel softer and easier to handle, it also helps to prevent static build-up during drying.