Microfiber choth is so called when the fibers used to produce the cloth weigh less then 1 gram er 9km(9,000m) of length. That's over 5 miles!
For most microfiber, this equates to a diameter of less than 0.012mm.
Microfiber is made up of two polymers, polyester and polyamide, which combine to form a single thread.

The softness, elasticity, and stability of microfiber cloths comes from its microporous structure hich is formed by the impregnation of polyurethane elastomer, similar to collagen in natural skin, into Ultrafine Microfiber.