Synthetic polymer materials, such as plastics and rubbers, have become ubiquitous in our daily lives. This is especially true for synthetic latex films, a type of nanoparticle-based films that are widely used in packaging, biomedicine, and electronics. Unfortunately, the latex films produced this way are weak, and organic solvents and fillers must be added to the initial mixture. These additives are not only expensive but also harmful to the environment. Recently, researchers have developed an innovative way to produce tough and crack-resistant elastic nanoparticle-based latex films without using such additives. The key to their approach was a novel molecular nanostructure known as rotaxane.