Lotus-Leaf-Inspired Biomimetic Coatings: Different Types, Key Properties, and Applications in Infrastructures

Abstract

A universal infrastructural issue is wetting of surfaces; millions of dollars are invested annually for rehabilitation and maintenance of infrastructures including roadways and buildings to fix the damages caused by moisture and frost. The biomimicry of the lotus leaf can provide superhydrophobic surfaces that can repel water droplets, thus reducing the penetration of moisture, which is linked with many deterioration mechanisms in infrastructures, such as steel corrosion, sulfate attack, alkali-aggregate reactions, and freezing and thawing. In cold-region countries, the extent of frost damage due to freezing of moisture in many components of infrastructures will be decreased significantly if water penetration can be minimized. Consequently, it will greatly reduce the maintenance and rehabilitation costs of infrastructures. The present study was conducted to explore any attempted biomimicry of the lotus leaf to produce biomimetic coatings. It focuses anti-wetting characteristics (e.g., superhydrophobicity, sliding angle, contact angle), self-cleaning, durability, and some special properties (e.g., light absorbance and transmission, anti-icing capacity, anti-fouling ability) of lotus-leaf-inspired biomimetic coating products. This study also highlights the potential applications of such coating products, particularly in infrastructures. The most abundant research across coating materials showed superhydrophobicity as being well-tested while self-cleaning and durability remain among the properties that require further research with existing promise. In addition, the special properties of many coating materials should be validated before practical applications.

Environmentally Responsive Materials for Building Envelopes: A Review on Manufacturing and Biomimicry-Based Approaches

“…In this context, materials capable of such functions may require complicated and resource-efficient manufacturing techniques, especially when the whole facade is made from these materials rather than only as a covering or coating [ 108 , 117 , 140 ]. However, few manufacturing techniques are environmentally responsive or even sustainable (based on its three pillars).…”

“…Hydrophobicity in materials and coatings is an attractive property in which biomimicry-based approaches have been actively used lately. Moisture and other sources of water may penetrate and react with the surfaces causing degradation due to corrosion, alkali–aggregate reactions, sealant failure, wind-induced delamination, freezing and thawing, sulfate attack, mold growth, wood decay, loss of thermal resistance of insulation, crack propagation, and water leakage, among others [ 117 , 118 , 119 ]. Several plants and animals’ skins have served as a source of inspiration to achieve this behavior.…”

“…Recently, Collins and Safiuddin [ 117 ] gathered a collection of materials that have been used as biomimetic coating materials, such as polydimethylsiloxane (PDMS), with a contact angle close to 170°; ultrafine powder coating (UPC), with a contact angle superior to 160°; carbon nanotubes (CNT), nickel (Ni), Ni/Nano-C, and Ni/Nano-Cu, with a contact angle of 155.5°; fluoro-octyl-trichloro-silane-titanium; Janus particles; diamond-like carbon; graphene oxide-silica (GO-SiO 2 ); calcium hydroxide [Ca(OH) 2 ]; Photopolymer (PP); Acrylic polymer (AP); antimony doped tin oxide/polyurethane (ATO/PU) film; PMMA (Polymethyl methacrylate); PPS/PTFE (Polyphenylene sulfide/polytetrafluoroethylene); copper (Cu); and zinc oxide (ZnO) films. One can find among their properties anti-corrosive behavior, dust-free behavior, anti-abrasion, self-cleaning, anti-fogging and anti-icing, and lubricant and surface coating capabilities.…”

Tribological Behavior of Bioinspired Surfaces

“…The foremost example of biomimicry is probably the design of flying machines by Leonardo da Vinci inspired by birds [ 7 ]. Although there are numerous instances, one of the most exciting areas where biomimicry has made a substantial contribution is the creation of superhydrophobic surfaces [ 8 , 9 ]. To obtain functional characteristics such as self-cleaning, non-wettable, anti-icing surfaces, lowering drag in submarines and other vessels, and for the self-propulsion of liquids in micro-channels, superhydrophobicity is necessary [ 10 ].…”

Natural features, wettability, and optical diffraction patterns on an elastomeric replica of a superhydrophobic leaf derived via soft lithography

“…Nano-and microstructures that developed from the natural evolution of biological materials continue to serve as inspiration in designing advanced surfaces for smart coatings [1], sensors [2] [3], energy applications [4], and optical devices [5]. Self-cleaning surfaces have been developed by mimicking the hierarchical superficial structures of superhydrophobic leaves from lotus [6], rice [7], and Colocasia plants [8].…”