Vinš Václav, Fransen Maurice, Hykl Jiří, Hrubý Jan
†Institute of Thermomechanics of the CAS, v. v. i., Dolejškova 5, Prague 8, 182 00, Czech Republic.
‡Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands.
J Phys Chem B. 2015 Apr 30;119(17):5567-75. doi: 10.1021/acs.jpcb.5b00545. Epub 2015 Apr 16.
Measurements of the surface tension of supercooled water down to -25 °C have been reported recently (Hrubý et al. J. Phys. Chem. Lett. 2014, 5, 425-428). These experiments did not show any anomalous temperature dependence of the surface tension of supercooled water reported by some earlier measurements and molecular simulations. In the present work, this finding is confirmed using a counterpressure capillary rise method (the counterpressure method) as well as through the use of the classical capillary rise method (the height method). In the counterpressure method, the liquid meniscus inside the vertical capillary tube was kept at a fixed position with an in-house developed helium distribution setup. A preset counterpressure was applied to the liquid meniscus when its temperature changed from a reference temperature (30 °C) to the temperature of interest. The magnitude of the counterpressure was adjusted such that the meniscus remained at the same height, thus compensating the change of the surface tension. One advantage of the counterpressure method over the height method consists of avoiding the uncertainty due to a possible variation of the capillary diameter along its length. A second advantage is that the equilibration time due to the capillary flow of the highly viscous supercooled water can be shortened. For both the counterpressure method and the height method, the actual results are relative values of surface tension with respect to the surface tension of water at the reference temperature. The combined relative standard uncertainty of the relative surface tensions is less than or equal to 0.18%. The new data between -26 and +30 °C lie close to the IAPWS correlation for the surface tension of ordinary water extrapolated below 0.01 °C and do not exhibit any anomalous features.
最近有报道称已测量了过冷水至-25°C的表面张力（Hrubý等人，《物理化学快报》，2014年，第5卷，425 - 428页）。这些实验并未显示出一些早期测量和分子模拟所报道的过冷水表面张力存在任何异常的温度依赖性。在本工作中，使用反压毛细管上升法（反压法）以及经典毛细管上升法（高度法）证实了这一发现。在反压法中，垂直毛细管内的液体弯月面通过内部开发的氦气分布装置保持在固定位置。当液体弯月面的温度从参考温度（30°C）变化到感兴趣的温度时，对其施加预设的反压。调整反压的大小，使弯月面保持在相同高度，从而补偿表面张力的变化。反压法相对于高度法的一个优点是避免了由于毛细管直径沿其长度可能变化而导致的不确定性。第二个优点是可以缩短高粘性过冷水因毛细管流动而产生的平衡时间。对于反压法和高度法，实际结果都是相对于参考温度下水的表面张力的表面张力相对值。相对表面张力的组合相对标准不确定度小于或等于0.18%。-26°C至+30°C之间的新数据接近国际水和蒸汽性质协会（IAPWS）对普通水表面张力在0.01°C以下外推的相关性，并且没有表现出任何异常特征。
