Nanoengineers at the University of California, San Diego are asking what might be possible if semiconductor materials were flexible and stretchable without sacrificing electronic function?
Today’s flexible electronics are already enabling a new generation of wearable sensors and other mobile electronic devices. But these flexible electronics, in which very thin semiconductor materials are applied to a thin, flexible substrate in wavy patterns and then applied to a deformable surface such as skin or fabric, are still built around hard composite materials that limit their elasticity.
Writing in the journal Chemistry of Materials, UC San Diego Jacobs School of Engineering professor Darren Lipomi reports on several new discoveries by his team that could lead to electronics that are “molecularly stretchable.”
Lipomi compared the difference between flexible and stretchable electronics to what would happen if you tried to wrap a basketball with either a sheet of paper or a thin sheet of rubber. The paper would wrinkle, while the rubber would conform to the surface of the ball.
“We are developing the design rules for a new generation of plastic--or, better, rubber--electronics for applications in energy, biomedical devices, wearable and conformable devices for defense applications, and for consumer electronics,” said Lipomi. “We are taking these design rules and doing wet chemistry in the lab to make new semiconducting rubber materials.”
While flexible electronics based on thin-film semiconductors are nearing commercialization, stretchable electronic materials and devices are in their infancy. Stretchable electronic materials would be conformable to non-planar surfaces without wrinkling and could be integrated with the moving parts of machines and the body in a way that materials exhibiting only flexibility could not be. For example, one of the chief applications envisioned by Lipomi is a low cost “solar tarp” that can be folded up for packaging and stretched back out to supply low cost energy to rural villages, disaster relief operations and the military operating in remote locations. Another long-term goal of the Lipomi lab is to produce electronic polymers whose properties--extreme elasticity, biodegradability, and self-repair--are inspired by biological tissue for applications in implantable biomedical devices and prosthetics.
Lipomi has been studying why the molecular structures of these "rubber" semiconductors cause some to be more elastic than others. In one project published recently in the journal Macromolecules, the Lipomi lab discovered that polymers with strings of seven carbon atoms attached produce exactly the right balance of stretchability and functionality. That balance is key to producing devices that are “flexible, stretchable, collapsible and fracture proof.”
Lipomi’s team has also created a high-performance, “low-bandgap” elastic semiconducting polymer using a new synthetic strategy the team invented. Solid polymers are partially crystalline, which gives them good electrical properties, but also makes the polymer material stiff and brittle. By introducing randomness in the molecular structure of the polymer, Lipomi’s lab increased its elasticity by a factor of two without decreasing the electronic performance of the material. Their discovery, published in RSC Advances, is also useful for applications in stretchable and ultra-flexible devices.
Catherine Hockmuth | newswise
Cost-efficiently modernising heating networks
11.02.2016 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
Demonstration of smart energy storage technologies and -management systems on the island of Borkum
11.02.2016 | Steinbeis-Europa-Zentrum
Today, plants and microorganisms are heavily used for the production of medicinal products. The production of biopharmaceuticals in plants, also referred to as “Molecular Pharming”, represents a continuously growing field of plant biotechnology. Preferred host organisms include yeast and crop plants, such as maize and potato – plants with high demands. With the help of a special algal strain, the research team of Prof. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam strives to develop a more efficient and resource-saving system for the production of medicines and vaccines. They tested its practicality by synthesizing a component of a potential AIDS vaccine.
The use of plants and microorganisms to produce pharmaceuticals is nothing new. In 1982, bacteria were genetically modified to produce human insulin, a drug...
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".
Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...
The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.
Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...
Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.
The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).
Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels
A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...
12.02.2016 | Event News
09.02.2016 | Event News
02.02.2016 | Event News
12.02.2016 | Physics and Astronomy
12.02.2016 | Life Sciences
12.02.2016 | Medical Engineering