Biomimetic Superhydrophobic Materials through 3D Printing: Progress and Challenges

Abstract

Superhydrophobicity, a unique natural phenomenon observed in organisms such as lotus leaves and desert beetles, has inspired extensive research on biomimetic materials. Two main superhydrophobic effects have been identified: the “lotus leaf effect” and the “rose petal effect”, both showing water contact angles larger than 150°, but with differing contact angle hysteresis values. In recent years, numerous strategies have been developed to fabricate superhydrophobic materials, among which 3D printing has garnered significant attention due to its rapid, low-cost, and precise construction of complex materials in a facile way. In this minireview, we provide a comprehensive overview of biomimetic superhydrophobic materials fabricated through 3D printing, focusing on wetting regimes, fabrication techniques, including printing of diverse micro/nanostructures, post-modification, and bulk material printing, and applications ranging from liquid manipulation and oil/water separation to drag reduction. Additionally, we discuss the challenges and future research directions in this burgeoning field.

Construction and Regulation of a Superhydrophobic Sponge via In Situ Anchoring of a Hyper-Cross-Linked Polymer for Efficient Oil/Water Separation

“…The HMFs were therefore tilted to slopes with different slide angles. When conditions of SA < 10° and CA > 150° are met at the same time, it can be considered to meet the conditions of the “lotus effect” . In addition to the contact angle (CA), the slide angle (SA) is another key factor for evaluating the superhydrophobicity.…”

Hydrophobic Coatings with Charge Permeability via Plasma Deposition of Long-Chain Perfluorocarbons

“…A classic example is the hydrophobization of surfaces with self-assembled monolayers of fluoroalkylsiloxane and alkylsiloxane brushes . Furthermore, by drawing inspiration from nature and manufacturing micro and nano hierarchical structures on the surfaces of hydrophobic materials, superhydrophobic wetting states can be achieved. , Typical examples for this are the lotus leaf wetting state: low adhesion surfaces with advancing contact angles above 150° and very low contact angle hysteresis, and the rose petal state: high adhesion surfaces with similarly high advancing contact angles, but low receding contact angles (high contact angle hysteresis) . However, in many of these cases, the substrates utilized for hydrophobization are typically limited to metal oxides because the process relies on the reaction of surface hydroxyl groups with incoming silane molecules dispersed in the organic solvent.…”

Chemical Instability-Induced Wettability Patterns on Superhydrophobic Surfaces

“…Bio-mimic superhydrophobic surfaces have drawn rapidly increasing research interest because of their great significance for versatile applications such as self-cleaning [ 1 , 2 ], chemical detection and sensors [ 3 , 4 , 5 , 6 ], liquid droplet/gas bubble manipulation [ 7 , 8 , 9 , 10 , 11 ], icephobicity [ 12 , 13 , 14 , 15 , 16 ], immiscible liquid separation [ 17 , 18 , 19 ], enhanced heat transfer [ 20 , 21 , 22 ], and anti-corrosion [ 23 , 24 , 25 ]. However, most superhydrophobic surfaces suffer from chemical instability in harsh conditions like highly concentrated acidic/alkaline/salty solution immersion, organic solvent invasion, thermal treatment, UV irradiation, and active species exposure [ 26 , 27 , 28 ].…”