Reducing Waste through Better Bottle Engineering
Frustrated when you can't get that last bit of shampoo out of the bottle? Engineers at Ohio State University have developed a coating that enables soaps and detergents to slide more easily out of their containers. The coating is made up of little y-shaped nanoparticles made of silica or quartz. After being treated, these y-shaped nanoparticles do not allow soap to stick to them. They also prevent the soap droplets from touching the inside of the bottle by holding them atop tiny air pockets.
Coatings already exist to help food get out of bottles, but soap is trickier. Soaps have very low surface tension, which cause them to stick to plastics easily. To create the coating, the researchers sprayed a mixture of solvent and silica nanoparticles into plastic bottles, causing the inside surface to soften. When the plastic re-hardened, the silica became embedded in the surface of the plastic. Positioning the y-shaped silica structures a few millimeters apart on the inside of the bottle prevents soap from touching the plastic, and causes it to form beads and roll off.
Although getting all of the product out of a shampoo bottle sounds like a frivolous problem, it has a big environmental impact. Billions of bottles with product still inside them end up discarded in landfills. This innovation will also help with recycling, since plastics must be rinsed clean before they can be recycled. The researchers have already applied the coating on other materials such as smartphone covers and headlights. They also hope that the technology can be used on biomedical devices that need to remain clean such as catheters.
Photo credit: Image from video by Philip S. Brown, courtesy of The Ohio State University.