If you wake up with knotty, frizzy hair, your pillowcase might be the culprit....

https://papa-wiki.win/index.php/Why_Does_My_Hair_Tangle_at_the_Back_of_My_Head_Overnight%3F

If you wake up with knotty, frizzy hair, your pillowcase might be the culprit. Standard cotton creates friction that snags delicate strands overnight