Researchers at the Technical University of Madrid have developed a cheap new method of manufacturing optical nanosensors that can cling to curved surfaces. The technique may allow for a widespread adoption of skin-worn health monitoring devices that will provide all-day tracking of parameters like body temperature, heart rate, and physical activity.
The technology relies on a combination of aluminum films, the polycarbonate coating used in compact disks, and standard Scotch tape. The aluminum film, only 100 nm thick, has a pattern of holes throughout its surface. The pattern defines how light moving through the film is modulated, revealing the underlying characteristics of the surface below.
Some details about the new sensor technology according to the Madrid team:
These flexible nanosensors enable us to measure refractive index variations of the surrounding medium and this can be used to detect chemical substances. Besides, they display iridescent colors that can vary according to the viewing and illumination angle, this property facilitates the detection of position variations and surface topography to where they are stuck at a glance.
The creation method for flexible nanosensors consists, firstly, on manufacturing sensors over a compact disc (CDs) of traditional polycarbonate, and secondly, transferring these sensors to adhesive Scotch tapes by a simple stick-and-peel procedure. This way, the nanosensors go from the CD surface to the adhesive tape (flexible substrate).