Nanotechnology used for Olympic logo
Scientists at Norwestern University have developed a new nano-printing technology called Polymer Pen Lithography. Polymer Pen Lithography uses arrays of tiny flexible pens made of polymers to print over large areas with nanoscopic through macroscopic resolution to scribe marks on various different nano-scales. This technique can print out tiny dot-matrix imagery and can find use in computational tools, medical diagnostics and the pharmaceutical industry. Polymer pen lithography merges the feature size control of dip-pen nanolithography with the large-area capability of contact printing. Because ink delivery is time and force dependent, features on the nanometer, micrometer, and macroscopic length scales can be formed with the same tip array. Arrays with as many as about 11 million pyramid-shaped pens can be brought into contact with substrates and readily leveled optically to ensure uniform pattern development. Beijing Olympics emblem has been mass-produced 15,000 times, each logo being so small the whole print run fits inside one square centimeter. 2,500 of the images, made of thousands of 90 nanometers dots, would fit on a grain of rice. This was demonstrated to mark the highlight that printing was one of ancient China's four great inventions.