Seersucker. I. Light-weight cotton fabric, with alternating crinkled stripes. 
It exists 2 kind of seersucker

1/100% cotton seersucker :
With weave differences in the stripes or with weave tension differences in the weaving process, you can get a good crinkle effect after having your cotton seercucker fabric dyed.

2/ PES/Cotton seersucker
With polyester stripes, cotton stripes and a soda treatment, you can get a crinkle effect because the differences between the textile materials don't have the same warp contractions after the treatment.