What invention was John working on before the war

Over lunch, Ann learns that Mr. Loomis worked for a man who invented a type of polymer that would repel radiation. The team had worked a long time and had just created a full suit made of this polymer and were waiting for the military to come see it when the war broke out. Mr. Loomis claims he was alone in the lab the night the nuclear bombs fell and this is how he was able to use the suit to search for other survivors. Mr. Loomis also tells Ann that his team created a filter for water and material to cover food and other items that could be contaminated with radiation. This is how Mr. Loomis survived on his walk to Ann's valley.