I am a new quilter,
I'm working on a quilt for my granddaughter (my first quilt)

its a disappearing 9 patch with applique on some of the squares
I was using a website to just browse some material
I have learned that I should not mix materials so I stick with 100% cotton
but on this websight there was quilting material listed as
"100% Cotton Poplin"

what is Poplin? is it the same as the quilting materials I have been using
most of them are well known names like Riley & Blake, Rose & Hubble, Adorn it, etc
is there any difference? like if I mixed some into my quilt

would that be something I should avoid? or would regret?

any help would be appreciated, thanks