Fabricating Durable Liquid-infused Surfaces with Affordable Porous Surface Features

Liquid-infused surfaces are emerging slippery surfaces inspired by Nepenthes pitcher plants. The slippery characteristics of these surfaces stem from the lubricant that is immiscible with the working fluid, which is entrapped within their surface features. The stability of these surfaces depends on the shape of surface asperities and lubricant type. These surfaces are severely susceptible to lubricant depletion under high shear stress. In this study, we manufactured surfaces with affordable reentrant cavities that can remedy this problem. In this method, we fabricated a solution, including polyurethane thinner and polystyrene particles. Then, the aluminum samples that were dip-coated in the abovementioned solution were immediately subjected to humid air that was provided by a humidifier device. By this means, tiny water droplets were condensed on the coated surface. As a result, the porous structures were formed with the evaporation of the trapped solvent at room temperature. The induced reentrant cavities were composed of semispherical pores, which could enhance the stability of the infused lubricant by affecting the Laplace pressure. The average size of these pores was ۴۵.۸۲ μm. After infusion with silicone oil with a viscosity of ۵ mPa.s, the contact angle of water reached ۱۰۳.۵° ± ۵°. To investigate the stability of lubricant within surface structures, the fabricated surfaces were subjected to shear stress by rotating them with a rotational speed of ۱۵۰۰ rpm. The contact angle of these surfaces did not significantly change after this test.

کلیدواژه ها:

coating ، durable liquid-infused surface ، hydrophobicity ، reentrant cavity ، wettability