Micro‐/Nanostructured Interface for Liquid Manipulation and Its Applications

Abstract

Understanding the relationship between liquid manipulation and micro‐/nanostructured interfaces has gained much attention due to the wide potential applications in many fields, such as chemical and biomedical assays, environmental protection, industry, and even daily life. Much work has been done to construct various materials with interfacial liquid manipulation abilities, leading to a range of interesting applications. Herein, different fabrication methods from the top‐down approach to the bottom‐up approach and subsequent surface modifications of micro‐/nanostructured interfaces are first introduced. Then, interactions between the surface and liquid, including liquid wetting, liquid transportation, and a number of corresponding models, together with the definition of hydrophilic/hydrophobic, oleophilic/olephobic, the definition and mechanism of superwetting, including superhydrophobicity, superhydrophilicity, and superoleophobicity, are presented. The micro‐/nanostructured interface, with major applications in self‐cleaning, antifogging, anti‐icing, anticorrosion, drag‐reduction, oil–water separation, water collection, droplet (micro)array, and surface‐directed liquid transport, is summarized, and the mechanisms underlying each application are discussed. Finally, the remaining challenges and future perspectives in this area are included.

A Superhydrophobic Droplet‐Based Magnetoelectric Hybrid System to Generate Electricity and Collect Water Simultaneously

“…Bioinspired superhydrophobic materials have low surface energy and micro‐ or nano‐scale surface roughness, [ 7–9 ] rendering their unique capability to manipulate water droplets. By carefully designing and controlling the superhydrophobic surfaces, water drops can pin, [ 10 ] roll, [ 11 ] separate, [ 12 ] jump, [ 13 ] and react [ 14 ] and, therefore, can possess a variety of applications, such as self‐cleaning coatings on solar cells, [ 15 ] oil/water separation, [ 16–18 ] microfabrication, [ 19,20 ] and anti‐biofouling.…”

Liquid Marbles in Liquid

“…[ 16–19 ] Compared with the uncoated “naked” droplets, LMs can be manipulated as non‐sticky fluidic cells with significantly reduced surface friction and increased drop operability. [ 20–22 ] Based on the nature of the internal fluid and variations of physical properties of coated particles, external stimuli such as electric field, [ 23–26 ] photon, visible light, [ 27 ] magnetic field, [ 28,29 ] and mechanical force [ 30–32 ] can be used to manipulate the LMs’ properties. In addition, LMs with shells composed of multilayers of particles can be engineered for precise control of chemical dosing by allowing them to coalesce and disintegrate at specific interval.…”

Tailoring Materials with Specific Wettability in Biomedical Engineering

“…[ 11 , 12 , 13 , 14 , 15 , 16 ] Thanks to these advances, the wettability materials have been employed in different applications depending on their own distinctive wetting performances. For example, the hydrophobic and oleophilic materials are usually applied for self‐cleaning, oil/water separation, anticorrosion, and anti‐icing fields; [ 17 , 18 ] the liquid‐infused surfaces could not only serve as anti‐icing and self‐cleaning materials, but also work for constructing optical devices; [ 3 ] the oleophobic and hydrophilic surfaces show practical values in antifogging, antifouling, filtration, and biomedical fields; [ 19 , 20 , 21 ] while hydrophobic and hydrophilic composite materials have the capacity of collecting water without energy input. [ 22 ] Especially, the well‐designed superhydrophobic and superhydrophilic surfaces show unparalleled advantages in precise and lossless liquid manipulation, [ 23 , 24 , 25 ] which further promotes the laboratory investigation and market‐oriented process of wettability materials.…”