Bionic surface diode for droplet steering

Abstract

Control of droplet sliding and its interfacial behavior such as sliding resistance and friction have important applications in microfluidic and energy-related fields. Nature provides many examples of interface-driven droplet sliding control; yet, to date, the continuous governing of the multiphase process and precise steering of droplet sliding remain challenging. Here, directional-dependent ultraslippery patterned surfaces with significant droplet sliding anisotropy were created by coordinating the heterogeneous wettability of the back of the dessert beetle, directionaldependent architecture of the butterfly wing, and ultraslippery configuration of the Nepenthes alata. Analysis of the sliding resistance on typical ultraslippery patterned surfaces reveals that the directional-dependent triple phase line (TPL) immigration on the ultraslippery patterns dominates the strong sliding anisotropy, which can be modeled using the classic Furmidge equation. In particular, the sliding anisotropy for the semicircular ultraslippery patterned surface shows threefold higher than that of natural butterfly wings due to the most significant difference in TPL immigration in two opposite directions, which enables the simultaneous handling of multiple droplets without mass loss and steering of droplet sliding/friction. This work may transform the design space for the control of multiphase interface motion and the development of new lab-on-a-chip and droplet-based microsystems.

Droplet interface in additive manufacturing: From process to application

“…Emulating the surfaces of living organisms in nature and exploring the mysterious surface properties are hot research topics in the area of surface and interface. 66,67 These engineered surfaces are generally complex and fine-structured, which makes it challenging to prepare them with traditional material processing methods. AM, with its high degree of design freedom and fabrication flexibility, is increasingly playing an irreplaceable role in the field of material surface and interface.…”

“…Emulating the surfaces of living organisms in nature and exploring the mysterious surface properties are hot research topics in the area of surface and interface 66,67 . These engineered surfaces are generally complex and fine‐structured, which makes it challenging to prepare them with traditional material processing methods.…”

Spontaneous Transport Mechanics of Water Droplets under a Synergistic Action of Designed Pattern and Non-Wetting Gradient

“…For instance, Leng et al summarize the mechanisms of water droplet manipulation on various biological surfaces. Yang et al explored multi-bioinspired SLIPS-patterned surfaces that allow for directional droplet sliding, and precise steering of droplet friction was created by coordinating the heterogeneous wettability of the back of the desert beetle, directional-dependent architecture of the butterfly wing, and ultraslippery configuration of N. alata.…”

“…For instance, Leng et al 15 summarize the mechanisms of water droplet manipulation on various biological surfaces. Yang et al 16 explored multi-bioinspired SLIPS-patterned surfaces that allow for directional droplet sliding, and precise steering of droplet friction was created by coordinating the heterogeneous wettability of the back of the desert beetle, directional-dependent architecture of the butterfly wing, and ultraslippery configuration of N. alata . Yang et al 17 reported three-dimensional (3D) topological SLIPS with an anisotropic-slippery-Wenzel state; fabricated rice leaflike grooved nanotextured SLIPS can properly shape the droplet footprint to achieve a sliding resistance anisotropy of 109.8 μN.…”

Solid-like Slippery Surface with Excellent Comprehensive Performance

“…Aizenberg et al developed a slippery-liquid-infused porous surface (SLIPS) inspired by Nepenthes, which has gained considerable attention . Owing to its excellent slippery performance, SLIPS shows application prospects in various fields, including anti-icing, corrosion resistance, antifouling, droplet transportation, and fog collection. − …”