I don't know...But I think it's consistence is partial solid,at least it looks like that,so a strong slicing technique from a swordsman with strong haki might do the job.It won't do much though since Law can spam it,but it might slow him down.
Hmmm but all attacks are contained inside it.So it has to have something that makes it solid in a way, to contain Law power and techniques.Otherwise his attacks would spread beyond it's limit...Maybe because it's Law attacks it's not affected,cause he doesn't want to harm it.
