"Scientists Discover Process for Transitioning Two-Layer Graphene into a Diamond-Hard Material on Impact
The innovation could enable development of a range of flexible, impenetrable materials capable of protecting the body and fragile objects
http://www.asrc.cuny.edu/2017/12/18/diamene-study/
the paper is here"
I'm always a bit dubious about claims made in publications from scientist looking for more funding (all scientists including me). When one talks about impenetrability, you're talking about "toughness" or strength not hardness. Diamonds are hard because of their crystalline structure that includes conjugated (alternating with single bonds) double bonds arranged in a crystalline lattice. Materials like this can be very hard, but because of their crystallinity, can also be brittle. Diamonds can be easily cleaved. As far as I know, the strongest, toughest, most impenetrable material is elongated polyethylene, basically the same stuff that's in plastic bags, but in a higher molecular weight version. This is because the polyethylene's molecule's backbones are held together by carbon-carbon single bonds, some of the strongest atom to atom bonds known. Honeywell makes a version of this tradenamed "Spectra". Many people think that Kevlar (DuPont tradename) is the strongest material around, but elongated high molecular weight polyethylenes are considerably stronger. An interesting application of this material is for hawsers or ropes for tying up large ships since the volume and weight of the ropes on ships is significant. It is also used for the more obvious applications like bullet-proof vests and helmet liners. I have a business acquaintance who makes bullet-proof vests and had a promotional film made of his being shot wearing one. He was literally standing behind his product. He's also nuts.