Researchers at the University of Glasgow's James Watt School of Engineering have developed a nanofabrication technique that imprints ultra-thin silver nanowires onto bendable, transparent polymer films, creating a shield against electromagnetic interference for the next generation of flexible electronics. The work, led by Jungang Zhang in the Microelectronics Lab headed by Professor Hadi Heidari, targets applications such as wearable and implantable healthcare monitors, whose delicate signals need protection from electromagnetic noise.
The method uses a non-uniform electric field to align the nanowires on thin polyimide film, a process called interfacial dielectrophoresis, before picosecond laser pulses weld the junctions between wires and strip back their insulating coating. The laser treatment cut electrical resistance by a factor of 46 and raised optical transparency by up to 10 per cent. The finished films, just 5.1 micrometres thick, achieved shielding effectiveness of more than 35 decibels across 2.2 to 6 gigahertz, blocking over 99.97 per cent of incident radiation.
Crucially for manufacturing, the team says the process could be scaled up without cleanroom facilities, and demonstration devices measuring 40 by 80 centimetres have already been produced, with shielding performance described as more than a thousand times better than films of non-aligned nanowires. The research, funded by the Engineering and Physical Sciences Research Council, is published in ACS Nano, and points towards practical, transparent electromagnetic shielding for medical wearables and beyond.