Anti-icing propagation and icephobicity of slippery liquid-infused porous surface for condensation frosting.

• A novel method of preparing the slippery lubricant-infused porous surface is proposed. • Condensation frosting is experimentally investigated on four typical substrates. • Directional icing propagation is impeded on the proposed slippery surface. • Molecular Dynamics simulation explores droplet wetting on slippery surfaces. Anti-propagation and enhanced icephobicity both are critical for anti-icing surfaces. In this work, four types of functional surfaces were prepared to investigate condensation frosting mechanisms (hydrophilic surfaces, hydrophobic slippery lubricant-infused porous surfaces, and two types of superhydrophobic surfaces). Experimental results indicated that no directional icing was identified on both the hydrophilic and slippery surfaces, while it was observed on superhydrophobic surfaces. The mechanisms were explained based on microscopic photos, together with theoretical analysis and Molecular Dynamics simulations. On the hydrophilic surfaces, the initially frozen droplets can induce the icing of some of their neighbours. However, these inter-droplet icing spreading failed to develop into a directional spreading for the whole field of view. On the slippery surfaces, most of the droplets had to freeze locally because the distances among them were beyond the effects of icing bridge. Moreover, the lubricant effects on droplet wetting were investigated using Molecular Dynamics simulation, and the results can support the existence of a lubricant layer beneath droplets. The surface icephobicity was experimentally investigated by measuring the critical shear stress of a frozen droplet. As a whole, the icephobicity of the slippery surface was significantly enhanced. Especially, when the substrate was chilled to −5 °C, the high icephobicity of the slippery surface was highlighted by an order of magnitude lower than that on the hydrophilic surface. Also, the slippery surfaces were fabricated based on silica nanoparticles via a commercially coating spray. This method can be of low economic cost for scalable preparation. Overall, the present work can be helpful for developing anti-icing functional surfaces. [ABSTRACT FROM AUTHOR]