Feb/March_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | F E B R U A R Y / M A R C H 2 0 2 1 9 role in the chemical reaction that makes polyurethane foams. While these new polyurethane foams could have myri- ad applications and even be manufac- tured with other kinds of biomass, the research group, in the second stage of their study, will use them in plant nurseries to help with plant growth. www.uco.es . FORMING GLASS MATERIALS Researchers from the Institute of Mechanics of the Chinese Academy of Sciences and Hong Kong University of Science and Technology recently con- ducted experimental studies for the first time on glassy systems composed of nonspherical particles. They found the monolayers of monodisperse ellipsoids are good glass formers and do not form local crystalline structures. Thus, they provide an ideal and general system for detecting the structural origin of slow- ing dynamics as the glass transition is approached. Glass formers have strong dynam- ic heterogeneities—some regions move fast while others move slow. These results show that structures with low structural entropy correspond well with slow dynamics, whereas fast relaxing regions have high structural entropy. The low structural entropy is a general structural feature of slow dynamics in glassy matter, which holds in systems composed of spheres and non-spheres. According to the researchers, “The observation of critical behaviors in ellip- soid glasses provides much more solid quantitative evidence of the thermo- dynamic nature of glass transition. The results shed new light on both the mys- teries of glass theory and designing ma- terialswithhigh stability and glass form- ing ability.” www.english.imech.cas.cn. Spatial correlations between slow-dynamics (red ellipses) and low-structural-entropy (light blue) regions in translational and rotational motion of colloidal ellipsoids with different aspect ratios. Courtesy of Yuren Wang.