Microfibre is a synthetic fibre that is microscopic compared to natural fibres. Ultra microfibres are 100 times smaller than a human hair and their star structure give a surface area 40 times greater than conventional cotton fibre. How Does Microfibre Work When Dry? When you drag a dry cloth or dusting head over a surface there are 40 times more fibres generating a positive electrical charge. This positive charge attracts dust which has a negative charge like a huge magnet. The fibres lock in the dust which is not released until proper laundering. How Does it Work damp? Polyamides attract greases and absorb them within their cell walls.