Externally Applied Electric Fields up to 1.6 × 10⁵ V/m Do Not Affect the Homogeneous Nucleation of Ice in Supercooled Water

Abstract

The freezing of water can initiate at electrically-conducting electrodes kept at a high electric potential, or at charged electrically-insulating surfaces. The microscopic mechanisms of these phenomena are unknown, but they must involve interactions between water molecules and electric fields. This paper investigates the effect of uniform electric fields on the homogeneous nucleation of ice in supercooled water. Electric fields were applied across drops of water immersed in a perfluorinated liquid using a parallelplate capacitor; the drops traveled in a microchannel and were supercooled until they froze due to the homogenous nucleation of ice. The distribution of freezing temperatures of drops depended on the rate of nucleation of ice, and the sensitivity of measurements allowed detection of changes by a factor of 1.5 in the rate of nucleation. Sinusoidal alternation of the electric field at frequencies from 3 to 100 kHz prevented free ions present in water from screening the electric field in the bulk of drops. Uniform electric fields in water with amplitudes up to 1.6±0.4×10 5 V/m neither enhanced nor suppressed the homogenous nucleation of ice. Estimations based on thermodynamic models suggest that fields in the range of 10 7 -10 8 V/m might cause an observable increase in the rate of nucleation.3

Supercooling of Water

“…The effects of an electric field however are still under debate. could find no effect on T het for DC fields up to 10 5 Vm -1 , and similarly Stan et al (2011) found no effect on T hom for fields up to 1.6*10 5 Vm -1 . In contrast, Wei et al (2008) found that fields of up to 1*10 5 V/m could affect the SCP, albeit by only 1.6 °C.…”

An Overview on Magnetic Field and Electric Field Interactions with Ice Crystallisation; Application in the Case of Frozen Food

“…Bartlett et al [57] reported that the use of 50 Hz FEF having strength of 2.5 × 10 5 V/m had no impact on the growth rate of ice crystals from water vapour. The strength of FEF can also affect the homogeneous nucleation of ice in supercooled water [55]. It was found that the FEF at frequency of 100 kHz and strength up to (1.6 ± 0.4) × 10 5 V/m neither enhanced nor suppressed the homogeneous nucleation of ice.…”

“…The effect of FEF on crystallization process depends on the frequency and intensity of FEF applied to the system [53][54][55]. For instance, Sun et al [53] studied the effect of FEF frequencies (frequency ranging from 50 Hz-5 MHz) on the degree of supercooling during freezing of a 0.9% NaCl aqueous solution at a relatively slow cooling rate (0.26 K/min).…”

“…It was found that the FEF at frequency of 100 kHz and strength up to (1.6 ± 0.4) × 10 5 V/m neither enhanced nor suppressed the homogeneous nucleation of ice. Furthermore, based on thermodynamic models, it was estimated that fields with the frequency of 100 kHz and strength ranging from 10 7 -10 8 V/m might cause an evident increase in the rate of nucleation [55].…”

“…More precisely, SEF tends to reduce the critical radius which in turn decreases the Gibbs free energy of the system and consequently increases the nucleation rate [12,35,55,[74][75][76][77][78]. Furthermore, application of SEF shortens the induction time [74].…”