Condensation control on biphilic jumping droplet surface*

Controlling condensation is crucial for applications such as thermal management or to maintain optical surface transparency in humid conditions. Condensation behavior can be controlled by surface structure: on nanoscale hydrophobic structures, droplets can jump out of the surface upon merging [1]. Making the nanostructures conical further amplifies the anticondensation property, as the jumping probability rises close to 100% [2]. The constant condensation removal allowed by the jumping mechanism significantly increases the heat transfer performance of the surface [3] and can be further improved by promoting nucleation with micrometric hydrophilic patterns [4]. Condensation removal limits the droplet size to the distance to its nearest neighbor which helps maintaining a good optical transparency. However, this distance depends on the random nucleation process and droplets nucleating far from each other will cover a large surface area before jumping which is detrimental for optical properties. In this presentation, we spatially control nucleation with biphilic patterns on a jumping droplet surface and study how it affects the condensation properties such as surface coverage, volume, or lifetime.

References

[1] Boreyko, J. B. & Chen, C. H., Physical review letters, 103(18), 184501, 2009.

[2] Mouterde, T. et al. Nature Materials, 16(6), 658-663, 2017.

[3] Miljkovic, N., & Wang, E. N. MRS bulletin, 38(5), 397-406. 2013.

[4] Hoque, M. J., et al. Cell Reports Physical Science, 3(4), 2022.