This is a very fun project! Use any easy-to-clean fabric for the collar: waterproof, wipeable cotton, tablecloth, faux leather, etc.
TIP: I like to use a waterproof fabric, but if you have in your stash just cotton, you can add the fusible lining inside to make it stronger (also, the bib will get some waterproof power :)
Pattern: msvillana.etsy.com
Happy sewing!