Abstract
The icephobicity of superhydrophobic surfaces can be defined by two different characteristics: the anti-icing property that shows how much a surface can delay the ice accumulation and the de-icing property that shows how difficult it is to remove the accumulated ice from a surface. This chapter presents the key properties of superhydrophobic surfaces for these two distinct icephobic properties, based on the recent experimental investigations of the anti-icing and de-icing properties measured under dynamic flow conditions and static conditions, respectively. The results suggest that high anti-icing efficacy cannot guarantee high de-icing efficacy due to their distinct icing mechanisms, which require different superhydrophobic surface properties for the respective icephobicity. For the anti-icing efficacy, a low depinning force or contact angle hysteresis of an impinging droplet on the given superhydrophobic surface is required, primarily affected by the contact line dynamics of the moving droplet. In contrast, for the de-icing efficacy, the robustness to retain the partial or fakir (i.e., Cassie-Baxter) wetting state of the freezing droplet is essential, mainly affected by the internal Laplace pressure and the additional thermodynamic processes accompanied by the freezing such as evaporation and condensation. The shape and dimensions of the structures of superhydrophobic surfaces significantly influence these effects. Taking into theoretical considerations of how they should determine the depinning force, contact angle hysteresis (i.e., advancing and receding contact angles), and the robustness of the Cassie- Baxter wetting state, we also propose predictive models that can benefit in the design of the superhydrophobic surfaces for effective and robust icephobicities.
Original language | English |
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Title of host publication | Ice Adhesion |
Subtitle of host publication | Mechanism, Measurement and Mitigation |
Pages | 361-388 |
Number of pages | 28 |
ISBN (Electronic) | 9781119640523 |
DOIs | |
State | Published - 1 Jan 2020 |
Keywords
- Superhydrophobicity
- anti-icing
- contact angle hysteresis
- de-icing
- depinning force
- icephobicity