Singh Navneet, Sood A K, Ganapathy Rajesh
Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India.
Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
Nat Commun. 2020 Oct 2;11(1):4967. doi: 10.1038/s41467-020-18760-7.
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.
液体在弯曲表面上的结构和动力学通常是通过基于受挫的玻璃化转变方法来研究的。然而，相互竞争的玻璃化转变理论在这类表面上在很大程度上仍未得到检验，而且迄今为止的研究完全是理论性/数值性的。在这里，我们对限制在球体表面的双分散胶体液体的动力学进行了单粒子分辨成像。我们发现，模式耦合理论很好地捕捉到了在中度到深度过冷状态下动力学的减慢。引人注目的是，在模式耦合交叉点附近，协同重排区域的形态从线状变为致密状，这是玻璃随机一级理论独有的预测。此外，我们发现在强曲率极限下，默明 - 瓦格纳长波涨落是无关紧要的，球体上的液体表现得像三维液体。因此，对相互竞争机制的比较评估是揭示玻璃化转变真正本质的关键一步。
