Cinemas theaters, restaurants and other establishments that don't want their clientele to use cell phones may soon have a new weapon: a nano technology-derived paint that can block cell phone signals. The paint, from a company called Natural Nano, uses copper particles, combined with a hardware blocking device, to block cell phone transmissions, while allowing other frequencies, including those used for emergency broadcasts, to get through. That distinction may allow the paint system to be sold legally in the US.

 engadgetmobile.com