Waterproof Paper

Hmmm....if you watched the video there was some kind of diagram on a whiteboard. It had a circle or an "O" (Oxygen?) with several parallel lines indicating either bonds or that it was traveling towards a large capital letter "P" (Phosphorus?). An arrow from "P" pointed to a little "pac-man" character, with the result showing at the bottom as a long carbon-based organic molecule. Apparently, "Pac-Man" was gobbling up something to form the resulting organic molecule which coats the surface of the paper.

My interpretation of this is that "metal-oxide" is a mis-nomer, since Phosphorus is a non-metal, yet oxides of Phosphorus are used as drying agents due to their anhydrous qualities, and so, logically, could be used as a coating to keep paper dry. I believe the diagram somehow indicates that that the phosphoric oxide (Phosphorus Pentoxide, P2-O5) reacts with the cellulose fibers of the paper. In fact, experiments have been done to crosslink cellulose acetate (itself created by exposing cellulose to an alkali) with phosphorus pentoxide. See the URL link below.

I am not a chemist or chemical engineer so this is just supposition based on the diagram I saw in the video. Any other thoughts?

http://www.msu.edu/~narayan/crosslinkingofcellulos e.pdf