Hydrogen-bond memory and water-skin supersolidity resolving the Mpemba paradox

• Main Authors: Zhang, Xi, Huang, Yongli, Ma, Zengsheng, Zhou, Yichun, Zhou, Ji, Zheng, Weitao, Jiang, Qing, Sun, Changqing
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Chemistry::Physical chemistry
• Online Access: https://hdl.handle.net/10356/103017; http://hdl.handle.net/10220/24395
• Institution: Nanyang Technological University

The Mpemba paradox, that is, hotter water freezes faster than colder water, has baffled thinkers like Francis Bacon, René Descartes, and Aristotle since B.C. 350. However, a commonly accepted understanding or theoretical reproduction of this effect remains challenging. Numerical reproduction of observations, shown herewith, confirms that water skin supersolidity [Zhang et al., Phys. Chem. Chem. Phys., DOI: 10.1039/C1034CP02516D] enhances the local thermal diffusivity favoring heat flowing outwardly in the liquid path. Analysis of experimental database reveals that the hydrogen bond (O:H–O) possesses memory to emit energy at a rate depending on its initial storage. Unlike other usual materials that lengthen and soften all bonds when they absorb thermal energy, water performs abnormally under heating to lengthen the O:H nonbond and shorten the H–O covalent bond through inter-oxygen Coulomb coupling [Sun et al., J. Phys. Chem. Lett., 2013, 4, 3238]. Cooling does the opposite to release energy, like releasing a coupled pair of bungees, at a rate of history dependence. Being sensitive to the source volume, skin radiation, and the drain temperature, the Mpemba effect proceeds only in the strictly non-adiabatic ‘source–path–drain’ cycling system for the heat “emission–conduction–dissipation” dynamics with a relaxation time that drops exponentially with the rise of the initial temperature of the liquid source.