#elecronics

Bioengineers Develop New Class of Giant Magnetoelastic Effect Human-Powered Bioelectronics

A team of bioengineers at the UCLA Samueli School of Engineering has invented a novel soft and flexible self-powered bioelectronic device. The technology converts human body motions — from bending an elbow to subtle movements such as a pulse on one’s wrist — into electricity that could be used to power wearable and implantable diagnostic sensors.

The researchers discovered that the magnetoelastic effect, which is the change of how much a material is magnetized when tiny magnets are constantly pushed together and pulled apart by mechanical pressure, can exist in a soft and flexible system — not just one that is rigid. To prove their concept, the team used microscopic magnets dispersed in a paper-thin silicone matrix to generate a magnetic field that changes in strength as the matrix undulated. As the magnetic field’s strength shifts, electricity is generated.

Nature Materials published today (September 30, 2021) a research study detailing the discovery, the theoretical model behind the breakthrough, and the demonstration. The research is also highlighted by Nature.

Researchers synthesize new liquid crystals allowing directed transmission of electricity

Liquid and solid—most people are unaware that there can be states in between. Liquid crystals are representative of one such state. While the molecules in liquids swim around at random, neighboring molecules in liquid crystals are aligned as in regular crystal grids, but the material is still liquid. Liquid crystals are thus an example of an intermediate state that is neither really solid nor really liquid¬¬. They flow like a liquid, and yet their molecules are grouped in small, regularly ordered units. A particular application of liquid crystals is optical imaging technology as in the screens of televisions, smartphones, and calculators. All LCD—or liquid crystal display—devices use these molecules.

Researchers at the Institute of Organic Chemistry at Johannes Gutenberg University Mainz (JGU) have synthesized novel liquid crystals in a project sponsored by the German Research Foundation (DFG). "If you slowly cool our liquid crystalline materials, the molecules align in a self-assembly process to form columns," explained Professor Heiner Detert of JGU. "We can imagine these columns like piles of beer mats stacked one on top of the other. But the special thing is that these columns conduct electrical energy along their whole length." The materials can thus serve as organic, liquid crystalline "power cables" and provide targeted electricity transmission in electronic components. While most materials conduct positive charges carried by holes, the new molecules actually conduct electrons. An additional advantage of a liquid crystalline power cable is that if it ruptures, any such rupture will heal entirely by itself.