Why does balloon ribbon curl?

I’ve pondered this at great length: why, when you scrape scissors down the side, does the balloon ribbon curl?

Welcome to the boards. I found this topic had previously been discussed here.

Most people in the other thread guessed it was due to fiber breakage. I have another WAG - I know that curly hair is straightened with heat because you’re breaking the hydrogen bonds in the hair proteins & causing them to reform in the straight position. Could ribbons curl in a similar manner?

WAG: Isn’t it because you flatten the ripples out on one side, leaving that side “longer” in length than the other rippled side, thus it will want to travel a longer path = outside of the curl? I wish I had some ribbon to look at around here…