2025-11-11 バージニア工科大学 (VirginiaTech)
＜関連情報＞
- https://news.vt.edu/articles/2025/11/eng-me-boreyko-electric-defrosting-102025.html
- https://onlinelibrary.wiley.com/doi/10.1002/smtd.202501143
- https://pubs.acs.org/doi/10.1021/acsnano.0c09153
静電デフロスト Electrostatic Defrosting
Venkata Yashasvi Lolla, Hongwei Zhang, Beckett Z. Socha, Rui Qiao, Jonathan B. Boreyko
Small Methods Published: 11 November 2025
DOI:https://doi.org/10.1002/smtd.202501143
Abstract
Electrification of ice has been studied for over half a century, mostly in the context of atmospheric science. Here, the polarizability and natural thermovoltage of a substrate-bound frost sheet are exploited for frost removal by placing an actively charged electrode overhead. This new technique, which we term electrostatic defrosting (EDF), can remove up to 75% of the frost’s mass from its substrate over a time scale of only minutes. A one-dimensional numerical model is developed to rationalize the effective electrostatic force exerted by the electrode on the warm end of the frost sheet. Experimentally, the effectiveness of EDF is shown to depend on the applied voltage, relative humidity of the ambient air, the gap height between the frosted substrate and the electrode plate, and the type of substrate. Although EDF primarily removes the dendritic frost structures rather than the underlying frozen condensate, this selective removal can still offer significant advantages for applications requiring improved visibility or reduced surface roughness. EDF can effectively remove frost without the application of heat, chemicals, or mechanical forces, rendering it a promising new construct for defrosting.
霜の静電跳躍 Electrostatic Jumping of Frost
Ranit Mukherjee,S. Farzad Ahmadi,Hongwei Zhang,Rui Qiao,and Jonathan B. Boreyko
ACS Nano Published February 24, 2021
DOI:https://doi.org/10.1021/acsnano.0c09153
Abstract
The electrification of ice has been a subject of research since 1940, mostly in the context of charge generation in thunderstorms. This generation of electric charge is spontaneous, distinct from applying an external electric field to affect the diffusive growth of ice crystals. Here, we exploit the spontaneous electrification of ice to reveal a surprising phenomenon of jumping frost dendrites. We use side-view high-speed imaging to experimentally observe frost dendrites breaking off from mother dendrites and/or the substrate to jump out-of-plane toward an opposing polar liquid. Analytical and numerical models are then developed to estimate the attractive force between the frost dendrites and liquid, in good agreement with the experimental results. These models estimate the extent of charge separation within a growing sheet of frost, which is caused by mismatches in the mobilities of the charge carriers in ice. Our findings show that the unexpected jumping frost event can serve as a model system for resolving long-standing questions in atmospheric physics regarding charge separation in ice, while also having potential as a deicing construct.
