There is nothing that compares to the effectiveness of 100% polyester in keeping your baby comfortable and dry. 

Polyester is hollow, and when an absorbent material is placed behind it, moisture will pass straight through the polyester into the absorbent layer, thereby keeping your baby comfortable and dry, which is wonderful for helping reduce the incidence of nappy rash, for fussy babies who don't like to feel wetness, and for a peaceful sleep overnight  zzzzzzz....

Polyester will lose its effectiveness if it becomes clogged with any type of residue like zinc based nappy creams and a build up of detergent.