A chance discovery could facilitate the transfer of electronic microstructures to uneven surfaces in the future - with sugar as a transport aid.
The golden lettering on a pillar that you can see in this picture seems unspectacular at first. In fact, they are microscopic letters on a single human hair. The letters "NIST" were imprinted with a mixture of sugar and corn syrup - actually a melted candy. NIST stands for the National Institute of Standards and Technology in the USA.
Gary Zabow, a physicist at NIST, wanted to send magnetic microdots to his colleagues in a biomedical laboratory for study. In order not to contaminate these microelectronic structures with plastic or chemicals, sugar came to his mind out of necessity: he embedded them in a lump of sugar. He accidentally gassed one of these sugar lumps containing magnetic points in a heated beaker. Contrary to expectations, when he washed away the viscous residue, the microscopic dots did not wash away with it. Instead, they had kept their exact original arrangement. This discovery made him wonder if sugar could be used as a transfer medium for microstructures.
Nowadays almost all of our technology is based on chips and semiconductors. These, in turn, usually consist of flat materials that are covered with tiny three-dimensional microstructures with great precision. Usually they are transferred by transfer printing with flexible ribbons or plastics. However, these materials often have problems conforming to sharp corners or curves. The liquid processes used to date also have problems with precision. However, the application possibilities for semiconductors and intelligent materials in biomedical or micro-robotic areas are growing and with them the need to transfer complicated microstructures to uneven materials.
However, using his candies as a transfer medium, Gary Zabow was able to achieve amazingly accurate results, as with the printed hair shown here. The new method is called REFLEX (REflow-driven FLExible Xfer) and could transfer microcircuit patterns like a stencil. “The semiconductor industry has spent millions of dollars perfecting the printing technology needed to make the chips. Wouldn't it be nice if we could use some of these technologies to extend the reach of these prints with something as simple and inexpensive as a candy?” Zabow comments on his discovery.