Electronic memory chips that bend and twist could soon power medical implants as a result of work by engineers at NIST (National Institute of Standards and Technology). The work is detailed on the July 2009 issue of IEEE Electron Device Letters. The engineers have found a way to build a flexible memory component out of inexpensive, readily available materials.

The new device is promising not only to its applications in medicine and other fields, but it also appears to possess the characteristics of a memristor (a fundamentally new component for electronic circuits that industry scientists developed in 2008) though they are not yet ready for the marketplace. NIST has filed for a patent on the flexible memory device. Electronic components that can flex without breaking are coveted by portable device manufacturers for many reasons - not just because people have a tendency to drop their mp3 players. For example, small medical sensors that can be worn on the skin to monitor vital signs such as heart rate or blood sugar could benefit patients with conditions that require constant maintenance. According to NIST researchers, though some flexible components exist, creating flexible memory has been a technical barrier.

The researchers took polymer sheets - the sort that transparencies for overhead projectors are made from - and experimented with depositing a thin film of titanium dioxide, an ingredient in sunscreen, on their surfaces. Instead of using expensive equipment to deposit the titanium dioxide as is traditionally done, the material was deposited by a sol gel process, which consists of spinning the material in liquid form and letting it set, like making gelatin. By adding electrical contacts, the team created a flexible memory switch that operates on less than 10 volts, maintains its memory when power is lost, and still functions after being flexed more than 4,000 times. The switch’s performance bears a strong resemblance to that of a memristor, a component theorised in 1971 as a fourth fundamental circuit element (along with the capacitor, resistor and inductor). A memristor is a resistor that changes its resistance depending on the amount of current that is sent through it - and retains this resistance even after the power is turned off. Industrial scientists had created this memristor the previous year and the NIST component demonstrates the same electrical behaviour but is also flexible. The NIST begin to explore the metrology that may be necessary in studying the device’s unique electrical behaviour.