消费者看到大量的选项的lively assortment of smart wearable electronics that wirelessly monitor vital boy signs, fitness or sun exposure to play music, charge other electronics or even purify the air. A team of University of Wisconsin-Madison engineers has created the world’s fastest stretchable, wearable integrated circuits, an advance that could drive the Internet of Things and a much more connected, high-speed wireless world. Led by Zhenqiang “Jack” Ma, the Lynn H. Matthias Professor in Engineering and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, the researchers published details of these powerful, highly efficient integrated circuits in the journal Advanced Functional Materials. The advance is a platform for manufacturers seeking to expand the capabilities and applications of wearable electronics- including those with biomedical applications - particularly as they strive to develop devices that take advantage of a new generation of wireless broadband technologies referred to as 5G. With wavelength sizes between a millimeter and a meter, microwave radio frequencies are electromagnetic waves that use frequencies in the .3 gigahertz to 300 gigahertz range. That falls directly in the 5G range. In mobile communications, the wide microwave radio frequencies of 5G networks will accommodate a growing number of cellphone users and notable increases in data speeds and coverage areas. In an intensive care unit, epidermal electronic systems (electronics that adhere to the skin like temporary tattoos) could allow health care staff to monitor patients remotely and wirelessly, increasing patient comfort by decreasing the customary tangle of cables and wires.
What makes the new, stretchable integrated circuits so powerful is their unique structure, inspired by twisted-pair telephone cables. They contain, essentially, two ultra-tiny intertwining power transmission lines in repeating S-curves. This serpentine shape - formed in two layers with segmented metal blocks, like a 3-D puzzle - gives the transmission lines the ability to stretch without affecting their performance. It also helps shield the lines from outside interference and, at the same time, confine the electromagnetic waves flowing through them, almost completely eliminating current loss. Currently, the researchers’ stretchable integrated circuits can operate at radio frequency levels up to 40 gigahertz. The advance could allow health care staff to monitor patients remotely and wirelessly, increasing patient comfort by decreasing the customary tangle of cables and wires. And, unlike other stretchable transmission lines, whose widths can approach 640 micrometers (or .64 millimeters), the researchers’ new stretchable integrated circuits are just 25 micrometers (or .025 millimeters) thick. That’s tiny enough to be highly effective in epidermal electronic systems, among many other applications. Ma’s group has been developing what are known as transistor active devices for the past decade. This latest advance marries the researchers’ expertise in both high-frequency and flexible electronics.
“我们已经找到了一种将高频活跃晶体管整合到一个有用的电路中的方法，”马云说，他的工作得到了空军科学研究办公室的支持。“这是一个平台。这为许多新功能打开了大门。”该论文的其他作者包括Yei Hwan Jung，Juhwan Lee，Namki Cho，Sang June Cho，Huilong Zhang，Subin Lee，Tong June Kim和UW-Madison的Shaoqin Gong以及中国电子科学技术的Yijie Qiu。
A new self-healing material could solve many wearable woes. The experimental electronics material works in high humidity and even after being cut in half - once it heals itself. The physical limitations of existing materials are one of main problems when it comes to flexible electronics, be it wearables, medical or sports tech. If a flexible material breaks, it either stays broken, or if it has some self-healing properties it may continue to work, but not so well. However, a team from Penn State have creating a self-healing, flexible material that could be used inside electronics even after multiple breaks. The main challenge facing researchers led by Professor Qing Wang, was ensuring that self-healing electronics could restore "a suite of functions". The example used explains how a component may still retain electrical resistance, but lose the ability to conduct heat, risking overheating in a hypothetical wearable, which is never good. The nano-composite material they came up with was mechanically strong, resistant against electronic surges, thermal conductivity and whilst packing insulating properties. Despite being cut it in half, reconnecting the two parts together and healing at a higher temperature almost completely heals where the cut was made. The thin strip of material could also hold up to 200 grams of weight after recovering.
Unlike other healable materials, the boron-nitrate nanosheets the Penn State team used are unaffected by moisture, meaning it could also be used in high humidity environments like the shower. "This is the first time that a self-healable material has been created that can restore multiple properties over multiple breaks, and we see this being useful across many applications," said Qing Wang. "We need conducting elements in circuits but we also need insulation and protection for microelectronics."

An ultrathin film that is both transparent and highly conductive to electric current has been produced by a cheap and simple method devised by an international team of nanomaterials researchers from the University of Illinois at Chicago and Korea University. The film - actually a mat of tangled nanofiber, electroplated to form a "self-junctioned copper nano-chicken wire" - is also bendable and stretchable, offering potential applications in roll-up touchscreen displays, wearable electronics, flexible solar cells and electronic skin. The finding is reported in Advanced Materials. "It's important, but difficult, to make materials that are both transparent and conductive," says Alexander Yarin, UIC Distinguished Professor of Mechanical Engineering, one of two corresponding authors on the publication. The new film establishes a "world-record combination of high transparency and low electrical resistance," the latter at least 10-fold greater than the previous existing record, said Sam Yoon, who is also a corresponding author and a professor of mechanical engineering at Korea University. The film also retains its properties after repeated cycles of severe stretching or bending, Yarin said - an important property for touchscreens or wearables.
制造是从聚丙烯腈或锅的纳米纤维垫子开始的，其纤维的直径约为人毛直径的一百分之一。Yarin说，纤维像迅速盘绕的面条一样射出，当沉积在表面上时，纤维会与一百万次相交。Yarin说：“纳米纤维在螺旋锥上旋转，但在飞行中形成分形环。”“循环有循环，因此它变得很长而且很薄。”裸板聚合物不进行，因此必须首先用金属涂层以吸引金属离子。然后将纤维用铜或银，镍或金电压。根据研究人员的说法，静电纺丝和电镀都是相对较高的商业上可行的过程，每个过程仅需几秒钟。Yarin说：“然后，我们可以采用金属镀纤维并转移到任何表面 - 手的皮肤，叶子或玻璃的皮肤。”额外的应用可能是纳米纹理表面，可显着提高冷却效率。Yoon说，通过在纤维连接处进行电镀的“自融合”“大大降低了接触性”。 Yarin noted that the metal-plated junctions facilitated percolation of the electric current - and also account for the nanomaterial's physical resiliency. "But most of it is holes," he said, which makes it 92% transparent. "You don't see it.