Chemists would say Todd Hoare is an engineer. Engineers would say he's a chemist. In truth, he's a little bit of both. Hoare works with hydrogels – networks of absorbent, flexible polymers that swell in water. They’re used in applications as varied as disposable diapers, burn dressings and explosives. (Just to be clear, there aren’t actually any explosives in Hoare’s lab).