Cooperatively rearranging regions change shape near the mode-coupling crossover for colloidal liquids on a sphere

• Published in: Nature communications Vol. 11; no. 1; p. 4967
• Main Authors: Singh, Navneet, Sood, A. K., Ganapathy, Rajesh
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 02.10.2020; Nature Publishing Group UK; Nature Portfolio
• Subjects: Colloids; Coupling; Dynamic structural analysis; Euclidean geometry; Euclidean space; Frustration; Glass transition; Liquids; Morphology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-18760-7

Abstract The structure and dynamics of liquids on curved surfaces are often studied through the lens of frustration-based approaches to the glass transition. Competing glass transition theories, however, remain largely untested on such surfaces and moreover, studies hitherto have been entirely theoretical/numerical. Here we carry out single particle-resolved imaging of dynamics of bi-disperse colloidal liquids confined to the surface of a sphere. We find that mode-coupling theory well captures the slowing down of dynamics in the moderate to deeply supercooled regime. Strikingly, the morphology of cooperatively rearranging regions changed from string-like to compact near the mode-coupling crossover—a prediction unique to the random first-order theory of glasses. Further, we find that in the limit of strong curvature, Mermin–Wagner long-wavelength fluctuations are irrelevant and liquids on a sphere behave like three-dimensional liquids. A comparative evaluation of competing mechanisms is thus an essential step towards uncovering the true nature of the glass transition.