That’s quite interesting! Is this your experiment? If so, you might heat a piece up again after the foam has been made, but this time with air to see if something like graphene oxide is made. It should become water soluble. This would then be a candidate for use with the Glowforge Nano technology and would represent a significant advance in technology as graphene oxide is somewhat difficult to make reliably. It should swell when soaked with water or alcohol.