Gradient-Wettable Multiwedge Patterned Surface for Effective Transport of Droplets against the Temperature Gradient.

With the rapid advancement of electronic integration technology, the requirements for the working environment and stability of the heat dissipation equipment have become increasingly stringent. Consequently, studying a high-efficiency gas-liquid two-phase heat transfer surface holds significant importance. Aiming at the limited liquid transport performance caused by the temperature gradient in the heat transfer process, this paper combines the wetting gradient with the shape gradient and proposes a gradient-wettable multiwedge patterned surface, where droplets can be transported over long distances and at high velocities. In this paper, the effect of the average wetting gradient on droplet transport performance is investigated by designing a multiwedge hydrophilic pattern and adjusting the wetting properties of the hydrophobic region. The study focuses on the temperature gradient resistance of gradient-wettable, multiwedge patterned surfaces, providing a mechanistic explanation of the surface's ability to resist temperature gradients through theoretical analysis. It is shown that the gradient wettability multiwedge patterned surface has better resistance to the temperature gradient that hinders the droplet movement, and the droplets can still achieve transport of ∼38 mm at an average speed of ∼158 mm/s under the temperature gradient of 0.59 °C/mm. The research in this paper provides some insights into the application of temperature gradient resistance on heat transfer surfaces and contributes to heat dissipation methods for electronic integrated environments.