Experimental investigation on anti-frosting characteristics of biphilic surfaces coupled with hygroscopic droplets for frosting control

Abstract

The inhibition of condensation frosting is of fundamental importance for various anti-frosting applications. However, icing on the entire surface is ultimately inevitable for most passive anti-frosting strategies due to the freezing of subcooled droplets on surface edge or defect and the subsequent frosting propagation. Herein, we design six patterned biphilic surfaces for changing the spatial distribution of hygroscopic droplets, and further control vapor diffusion flux during the initial stage of condensation frosting, achieving efficient and long-lasting frost prohibition. Discontinuous Ringlike stripe Biphilic with breakpoint overcomes the inhomogeneous accumulation behavior of the hygroscopic solution and enhanced surface water vapor pressure field, which delays the emergence and freezing of condensing droplets on the surface and reduces the frost propagation velocity. Under conditions of a surface temperature of −10 °C and a relative humidity of 50 %, the overall anti-icing duration reached 386–423 min, with the frost delay time being 15 to 20 times longer than that of conventional superhydrophobic surfaces. The results highlight the critical role of the surface water vapor pressure and vapor flux in influencing the kinetics of condensed droplet embryo formation and frost propagation kinetics, expand the application of hygroscopic solutions and biphilic surfaces, and provide valuable insights into the design of surfaces with tailored antifreeze properties for a variety of applications