Smart Materials behave differently depending on conditions such as temperature. Nitinol is a shape memory alloy. It is a metal alloy. When it's very cool you can bend it, if it is bent too far it stays bent. If you heat it to a certain temperature it goes back to a remembered shape. It is used in dental braces, it warms up in the mouth and pulls the teeth as it goes back to a remembered shape.
Nanoparticles are very, very samll. They contain roughly a few hundred atoms…