Microfiber is the terminology used to describe ultra-fine manufactured fiber. Fibers made using microfiber technology, produce fibers which weigh less than 0.1 denier. So what does that mean? It means that microfibers are two times finer than silk, three times finer than cotton, eight times finer than wool, and one hundred times finer than a human hair. The best way to understand microfiber is to look at a cross section of the fiber itself. In the diagram below it shows how the fiber is sliced into wedges (polyester) and attached to spokes (polyamide). Splitting the fiber ends further increases the surface area thus making it even more absorbent. Polyester wedges have the ability to scrape away microscopic bits of dirt while the polyamide spokes create a wicking action that pulls liquid into the fiber.
The ratio of the polyester and polyamide blend is important. The higher the content of polyamide the better the absorption. 80% polyester and 20% polyamide is typical. 100% polyester will not absorb water. When woven into cloth it has a soft feel, like cashmere or silk.