SensNews Aug 2020

23 Sensor100 August 2020 A colorful detector: Crystalline material reversibly changes color when absorbing water Researchers at the University of Tsukuba have developed a new kind of color-shifting crystalline material that can be used to indicate the presence of water.The change in hue is dramatic enough to be gauged by the unaided human eye.This work could lead to the creation of highly sensitive "vapochromic" sensors that can show if a particular gas or water vapor is present without the need for external power. "The aromatic carbazole dendrimers containing carbon rings are anchored to a diben- zophenazine core," explains senior author Professor Yohei Yamamoto. "Interestingly, even though van derWaals forces are usually considered to be relatively weak, the crystal stays together during operation." "This work can lead to a new class of gas sensors that can work in difficult to reach locations, because they do not require ex- ternal power." Science Daily A ugust 25 Color-Changing InkTurns Clothes into Giant Chemical Sensors A silk-based substance could lead to new wearables Researchers at Tufts University's Silklab say their new silk-based inks can respond to, and quantify, the presence of chemicals on or around the body. Silk's ability to “act like a protective ‘cocoon’ for biological ma- terials” means the necessary sensing and color-changing compounds can be added to the ink without losing their function, says Fiorenzo Omenetto, a biomedical engineer at Silklab and senior author of a new paper on the technology published in July in Advanced Materials. Colorimet- ric devices can vary in size and a sensing Tshirt based on a colorimetric pattern is developed to illustrate the utility that such formats can add to the wearable interface space. Tufts University Press Release June 2020