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

https://bizzmarkblog.com/do-i-need-silk-to-reduce-frizz-or-can-i-just-change-my-habits/

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