For $60, a company called Liquipel will take your smartphone, place it in a vacuum and pump a vapor into the chamber. The vapor deposition process spreads a thin film over and inside the device, coating the sensitive electronics with a material designed to deflect water -- what this material is made of remains a secret. Another nanocoating maker, P2i, gets a little more scientific with the explanation: "P2i's patented technology employs a special pulsed ionized gas (plasma), which is created within a vacuum chamber, to attach a nanometre-thin polymer layer over the entire surface of a product. When liquids come into contact with it, they form beads and simply run off" [source: P2i].
Before coating electronics with their material, P2i used it to waterproof outdoor equipment like gloves and hiking boots. Another company, HZO, is also protecting electronics with a waterproof nanocoating. But are these thin films really "waterproof?" Yes and no. These nanocoatings are designed to save devices from brief exposure, not minutes or hours spent underwater.
HZO writes that "many devices we have coated have survived continuous hours under water," but all three companies make it clear you shouldn't go swimming with your phone [souce: HZO]. They can repel water, and prevent components from being damaged by water, but you should still turn your phone off if it gets wet and give it time to completely dry off before using it.