Facile Adhesion-Tuning of Superhydrophobic Surfaces between “Lotus” and “Petal” Effect and Their Influence on Icing and Deicing Properties

Abstract

Adhesion behavior of superhydrophobic (SH) surfaces is an active research field related to various engineering applications in controlled microdroplet transportation, self-cleaning, deicing, biochemical separation, tissue engineering, and water harvesting. Herein, we report a facile approach to control droplet adhesion, bouncing and rolling on properties of SH surfaces by tuning their air-gap and roughness-height by altering the concentrations of poly dimethyl-siloxane (PDMS). The optimal use of PDMS (4-16 wt %) in a dual-scale (nano- and microparticles) composite enables control of the specific surface area (SSA), pore volume, and roughness of matrices that result in a well-controlled adhesion between water droplets and SH surfaces. The sliding angles of these surfaces were tuned to be varied between 2 ± 1 and 87 ± 2°, which are attributed to the transformation of the contact type between droplet and surface from "point contact" to "area contact". We further explored the effectiveness of these low and high adhesive SH surfaces in icing and deicing actions, which provides a new insight into design highly efficient and low-cost ice-release surface for cold temperature applications. Low adhesion (lotus effect) surface with higher pore-volume exhibited relatively excellent ice-release properties with significant icing delay ability principally attributed to the large air gap in the coating matrix than SH matrix with high adhesion (petal effect).

Designing Multifunctional Protective PVC Electrospun Fibers with Tunable Properties

“…Recently, great attention in the scientific community has been paid to the design of engineered wettability surfaces [ 1 ] due to their potential applications in a wide variety of industrial applications such as air filtration [ 2 , 3 ], oil/water separation [ 4 , 5 , 6 ], anti-icing [ 7 , 8 ], antibacterial [ 9 ], self-cleaning [ 10 ] or even corrosion resistance surfaces [ 11 ], among others. Multiple biological surfaces can be found in nature which exhibit a superhydrophobic behavior such as lotus leaves, duck feathers, or legs of the water strider and due to this, the development of bioinspired superhydrophobic surfaces is a continuous challenge [ 12 ].…”

Single-step plasma-induced hierarchical structures for tunable water adhesion

“…The main reason for the difference between these two evaporation behaviors is the pinning of the water droplets onto the contact region of the water droplet. The hybrid high-adhesive surfaces form the continuous TCL, even at high CAs, from covering the surface cavities conformally by water 18,[21][22][23] , resulting in the contact line hardly receding by the pinning of the contact line along the surface of the WZ wetting micro-wall. On the other hand, as the TCL becomes discontinuous on the low-adhesive surfaces, resulting in reduced water contact area in micro or nanoscale 19,20 , the water droplets can easily evaporate while retaining their spherical shape due to the receding of the contact line without pinning during evaporation in the steady CB wetting state.…”

“…Research has revealed that, as the TCL becomes discontinuous by lowering the contact area due to micro or nanoscale features and the scale of individual TCL becomes smaller, the air-pocket between the structures becomes stable, decreasing the water adhesion 19,20 . Conversely, certain surfaces form the high water adhesion, even at high CAs, with water penetrating through the surface cavities to increase the contact area, ultimately resulting in the formation of the continuous TCL 18,[21][22][23] . These findings underscore the importance of appropriately selecting the required structure and its smart combination, such as the hierarchical or hybridized structures, to control the adhesion of the superhydrophobic surfaces.…”

Droplet re-icing characteristics on a superhydrophobic surface

“…9,10 Besides basic studies on icing, many anti-icing methods are proposed to suppress the ice accretion, one of which is the application of nanoengineered surfaces. 11,12 Researchers fabricated numerous surfaces with various structures and wettability with the purpose of delaying the ice nucleation, [13][14][15] retarding the ice propagation, 16,17 reducing the ice adhesion, 18,19 and even self-cleaning subcooled droplets or melting frost by a kind of self-jumping behavior, [20][21][22][23][24][25] and have achieved expected results.…”