What Are Microfiber Cloths, And How Do They Clean So Well?

Sometimes when you’re a professional, the tools used by regular folks just won’t do. Formula One racers have those games console-looking steering wheels; award-winning photographers depend on more than the lens on their smartphone; and housekeepers, maids, cleaners, janitors, and other professional tidier-uppers use microfiber cloths. 

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But what actually are these special towels, and why are they so useful for cleaning? Well, it’s surprisingly technical – so here’s what’s going on.

What is a microfiber cloth?

Technically, a “microfiber” is simply a fiber finer than one denier, with a diameter of less than 10 micrometers. For comparison, that’s somewhere in between the width of a single human hair and a single red blood cell – or to use a scientific term, “pretty darn small”. 

Being that thin means all microfibers are synthetic – natural fibers simply don’t come that fine. Most are made from polyesters, polyamides, or a combination of the two, and the very best – at least, for cleaning – will be so-called “split” microfibers. 

“When microfibers are split, they are 200 times thinner than a single human hair,” explains the University of California, San Francisco, in a factsheet for its Environmental Health in Early Care and Education Project. “These split microfibers become much more absorbent.”

Indeed, microfibers can absorb seven times their own weight in water – perhaps not impressive next to cotton’s ability to hold up to 27 times its own weight in water, but when you factor in microfibers’ other advantages over the natural fabric, it’s clear why so many professionals prefer it. Microfiber can be used dry, or with water only – experiments in hospitals have shown that even without specialist detergents, moistened microfiber cloths can remove up to 30 percent of viable bacteria on surfaces, and may even be the preferred option in certain environments like neonatal units.

And of course, when doubled up with disinfectants, microfiber’s cleaning power is seemingly unbeatable, at least until some kind of nanofiber cloth is invented. At least one study found that this combination can destroy more than twice as many bacterial colonies as traditional cleaning methods, and in certain areas – places like the toilet and shower, where the real nasties turn up – it was more than nine times as effective as normal cleaning techniques.

“Until microfiber, cotton was the only option,” Darrel Hicks, cleaning industry consultant and author of Infection Prevention for Dummies, told industry magazine CleanLink in 2016. “Microfiber came along and completely changed the old rag-and-bucket way of doing things. Microfiber has improved the cleaning process in a revolutionary way.”

But how?

How do they work?

The superior cleaning ability of microfiber cloths comes from three factors – and the first is simple: it’s their oversized surface area. 

“A microfiber cloth simply has more threads per gram,” explains the Association for Cleaning Research (VSR). That means more fibers in contact with the surface and more surface area of the fiber to bind dirt for greater mechanical cleaning capacity.”

Such a lot of these teeny-tiny fibers woven together – especially when they’re split fibers – give a cloth that has the same surface area as a piece of cotton four times as large. And, just as with the bristles on a toothbrush or the rough, prickly burr of a fruit that you find caught in your pet’s coat, so many miniscule fibers being packed into a small space means an exceptional ability to glom onto things – be it plaque, fur, or in this case, specks of dirt so tiny that a normal cloth fiber probably wouldn’t even notice it.

Moreover, “the fiber has sharp angular edges when seen under high magnification, and the structure is such that it traps and holds oil and dirt well,” VSR points out. “Because the fibers are so thin, their fine texture is better at getting into nooks and crannies.”

But that’s not all microfiber has going for it. The fabric also benefits from a couple of phenomena from the world of physics: first, the strong capillary action, and secondly, a neat piece of physics known as the van der Waals force.

“Capillarity (or capillary action) [….] means that fluid is drawn up into a tube (hollow space) against the force of gravity,” VSR explains. “Such tiny tubes are called capillaries. The finer the capillaries, the higher the water can be drawn up.”

Now, this doesn’t remove dirt and bacteria just by virtue of existing – otherwise any old sponge would be able to match the cleaning power of a microfiber cloth. But thanks to microfiber’s unique structure of super-fine, super-densely packed fibers, the capillary action is much more powerful than that of a normal cloth. On top of that, “the tiny, wedge-shaped fibers can get into surfaces much better than round fibers,” VSR points out, “including getting into the crevices and irregularities in the surface, and are much better at forcing out attached dirt.”

Finally, there’s the van der Waals forces – kind of like a sort of “mini-gravity” that occurs between certain particles. These forces can help the cloths act like a vacuum cleaner, sucking up the dirt particles and sticking them to the tiny fibers of the fabric.

Here’s the thing though: van der Waals forces are actually some of the weakest forces around. They only really affect anything at the molecular level, and they’re fairly vaguely defined – identified basically by ruling out any other potential explanation for particles being attracted or repulsed from one another. So, how can such a small force make a difference to the cleaning prowess of a microfiber cloth? 

Well, again, it comes down to the microscopic structure of the fabric: essentially, even a tiny amount of force will add up when multiplied over millions of individual microfibers. It is, perhaps surprisingly, the same process that allows geckos to stick to the ceiling – their feet are equipped with millions of microhairs known as spatulae, each with a diameter of just 0.2 micrometers, which you may recognize as being two orders of magnitude smaller than even microfibers. With such a lot of these hairs, the combined force is enough to keep a whole-ass lizard on… der Waals, you might say.

The problems with microfibers

So, do microfiber cloths offer nothing but advantages? Unfortunately, no: there’s one pretty big drawback that we’ve neglected to mention so far, and that’s our old friend microplastic pollution.

“Microplastics are turning up everywhere, from remote mountain tops to deep ocean trenches. They also are in many animals, including humans,” wrote Judith Weis, Professor Emerita of Biological Sciences at Rutgers University, in a 2024 article for The Conversation.

“The most common microplastics in the environment are microfibers,” she explained – and “the biggest source is synthetic fabrics, which constantly shed them.”

To reduce your microfiber pollution footprint, then, make sure you don’t wash your cloths with detergent – that encourages microfiber shedding – and do fewer, fuller loads to reduce friction against cloths. Use cold water, and dry your laundry on a clothesline instead of tumble drying it, and, ideally, add a microfiber filter to your washer.

“Several brands of external filters are available that can be retrofitted onto existing washing machines,” Weis advised. “External filters can remove up to 90 percent of microfibers from rinse water.”

“The eventual solution will be reengineered textiles, which won’t shed, but it will take some time to develop them and move them into clothing supply chains,” she wrote. “In the meantime, filters are the most effective way to tackle the problem.”