Research at FAST

11 Impact Stories Highly Conductive and Stable Fiber for Wearable Electronics Dr Yang Chai and Dr Yu Wang, in close collaboration with Prof. Xiao-ming Tao in the Institute of Textiles and Clothing, have been investigating flexible electronic materials and fiber-based devices. Conductive fiber or fabric is indispensable to wearable electronics. Conductivity is usually achieved by coating fibers with a very thin metal coating. This coating must have negligible effect on the substrate, be compatible with the electronics fabrication process at low temperatures, and survive mechanical abrasion, bending, twisting and washing. Corrosion, especially due to washing and perspiration, has been a critical problem of fiber-based wearable electronic devices. To avoid corrosion, most fiber- based devices must be packaged in a water and gas-tight manner making it challenging to maintain the conductivity and stability of the metal coating. Dr Chai and his collaborators have developed an innovative drape-coating method using highly impermeable graphene as a protective layer for the metal coating, significantly reducing the metal coating’s corrosion. Creating and Improving Products for China’s Largest Medical Ultrasound Producer Prof. Jiyan Dai and his research group have been improving medical ultrasound transducers, piezoelectric devices that generate high-frequency sound waves to detect and form images of human organs and tissues, for the last 15 years, aiding accurate diagnoses and therapeutic treatments in hospitals. Prof. Dai’s innovative research solution has increased ultrasound beam focus and increased bandwidth by 30% compared to previous techniques. Ultrasound imaging resolution increases in both lateral and axial directions. A patent, filed in 2009, has been licenced (Rotational Ultrasound Imaging System ( 旋轉超聲成像系統 ) , Chinese Patent: ZL201010 542689.2). This research has received RMB 5.3M funding from the National Basic Research Program (973) of China and HK$6.5M in total from 3 competitive ITF grants. Prof. Dai’s research collaboration with the Shantou Institute of Ultrasonic Instruments Co. Ltd. (SIUI) has improved existing product performance, helped develop new products (one already on the market, a second in clinical trials, and a third in production), and delivered training that boosts the company’s R&D capabilities. These innovations have made the company more internationally competitive. Products improved or developed through PolyU research have achieved over HK$20M in sales. Overview Silver coated fabrics can be used to monitor a human body’s electrocardiographs, with performance comparable to commercial rigid electrodes. This technology can be used to create stretchable sensors, electrical connecting tracks, fabric circuit boards and fabric antenna. This technology greatly enhances wearable sensor reliability and has enabled development of comfortable and effective products. An L10LC thyroid scan (right hand side) compared to a traditional lower frequency transducer. SIUI’s website notes, “At the trade show this year, SIUI's brand new ultrasound imaging solutions - Apogee 6500 - attracted a lot of attention with their intelligent processing technology, excellent image quality, high working efficiency and ergonomic design. Moreover, equipped with a high frequency probe whose center frequency is over 10MHz, Apogee 6500 is able to produce outstanding performance in peripheral nerve and musculoskeletal ultrasound. It has won great admiration from all the professionals by showing images with high resolution even on difficult patients.” Corrosion problem of fiber-based wearable electronic devices because of human perspiration, sweat and washing. Graphene coating makes it highly stable.