Researchers at Harvard University’s School of Engineering and Applied Science, have according to a report on the University web site, invented a wholly new kind of anti-freeze that prevents frost from building up on metal surfaces. Based on nano-technolgy, the team reports in their paper published in the June issue of ACS Nano, that their new material when used as a coating has proven to be significantly better at preventing or reducing frost build-up on treated metal walls inside of a freezing unit on the university campus.
According to the report on the university site, the new process involves creating a surface that is flat at the molecular level using a nanostructured solid. The result is a new material they call Slippery Liquid Infused Porous Surfaces, or more easily, SLIPS. Nanostructures are materials that are created and/or modified at the molecular level and because the new material is so perfectly flat, water vapor cannot build up on its surface leading to frost or ice.
In addition to preventing cars and freezers from suffering the ill effects of frost build up (keyholes that won’t take a key, etc.) metals that can exist in extremely cold conditions would be useful for airplane parts, ships, spacecraft and when constructing buildings or other objects that need to exist in cold environments.
The team says their research was inspired by the simple lotus leaf which has puzzled scientists for years with its ability to prevent frost from building up on its leaves, thus saving itself from burns that kill most other plants in the same environment. New research has shown that the lotus works its magic by growing leaves with surfaces that are so flat that when viewed under a microscope, no imperfections, bumps or other deviations can be seen. When icy dew surrounds the plant, it simply slides off, and that’s exactly how the new coating developed by the team at Harvard works. Frost just slides off, creating a small pile at the base of a metal wall.
The team says that once they developed the coating, they found that they also had to develop a metal treatment to smooth the metal surface beforehand. The result is a two step process that can make such varied objects as metal hand railings, ship steps, airplane wings and even simple aluminum foil, impervious to frost buildup, making them much easier to use and in many cases, safer. Also, as a bonus, the treatment and coating are non-toxic and they don’t rust or corrode.