Surface Tension of Supercooled Water: Inflection Point-Free Course down to 250 K Confirmed Using a Horizontal Capillary Tube

Abstract

The temperature course of the surface tension of supercooled water was suspected to exhibit an anomalous featurethe so-called second inflection point (SIP). Besides some theoretical and molecular simulation studies, this hypothesis was primarily supported by experimental data by P. T. Hacker [NACA TN 2510, 1951]. Recently, the present group performed accurate surface tension measurements down to −26 °C using a modified capillary rise [Hrubý et al. J. Phys. Chem. Lett 2014, 5, 425 and Vinš et al. J. Phys. Chem. B 2015, 119, 5567] which, in contrast to Hacker’s data, showed no SIP anomaly. To confirm that the qualitatively different observations are not related to some fundamental phenomenon, we developed an experimental device employing basically the same method as Hacker with a horizontal capillary tube. New experimental data for the surface tension of supercooled water measured with the horizontal capillary setup down to −23 °C are presented in this study. The new data show a very good agreement with the previous capillary rise measurements. It was confirmed that the temperature dependence of the surface tension is free of SIP in a temperature range from −23 to 23 °C and can be well-represented by the IAPWS standard extrapolated below 0.01 °C. However, a small systematic deviation from the IAPWS correlation can be seen at temperatures below −15 °C.

The temperature dependence of the surface tension of water

“…We will use the value = 1.26. We have used the data collected by Pátek et al [27], and we have included some new data sets, for example the last measurements in supercooled water [30]. We have recalculated all temperatures in experimental data points into ITS 90.…”

Surface tension of aqueous binary mixtures under the supercooled conditions – Development of the measuring technique and preliminary data for water + lower alcohols

“…As the presented data have preliminary character, the standard uncertainty of the resulting surface tension is estimated relatively large u(σ) ≤ 0.80 mN m -1 compared to pure water measurements with the maximum uncertainty of around 0.40 mN m -1 [3][4][5]. Main sources of the uncertainty are coming from the uncertainty of the IAPWS correlation [11] for the surface tension of pure water at the reference temperature of +15°C u(σ IAPWS ) = 0.37 mN m -1 , which is used in the determination of the capillary tube inner diameter, and from the density of the binary mixture, which is considered quite large u r (ρ) = 1.0 % as it contains also the uncertainty of the mixture composition.…”

“…The surface tension was expected to show another anomaly referred as the SIP (second inflection point) anomaly in its temperature trend at temperatures close to -8°C. However, the existence of SIP was recently refuted down to -26°C by our experiments [3][4][5].…”

“…In this work, the experimental apparatus and the measuring technique used for the measurement of the surface tension of pure supercooled water [3][4][5][6][7] was modified such that it allows for investigation of aqueous binary mixtures. The new accurate data for the surface tension of aqueous systems, such as mixtures with alcohols or salts, under the supercooled conditions are important for scientific communities focused on the atmospheric and oceanographic research [8,9] and on the investigation of anomalous behaviour of water systems at low temperatures [1,2].…”

Unravelling the microphysics of polar mesospheric cloud formation

“…where Q is the particle charge, and ε0 and εr are the permittivity of vacuum and the relative permittivity of water, respectively. For the surface tension of ASW we use σASW= (114.8-0.144•T [K]) mN m -1 , a parameterization which is based on a low-temperature extrapolation of measured data for supercooled water (Vinš et al, 2017). Our previous study on the vapour pressure of ASW indicates that this parameterization is consistent with the properties of ASW to within 10% at the 15 investigated temperatures between 133 and 147 K (Nachbar et al, 2018c).…”