CHAPTER 5. Lotus Effect-based Superhydrophobic Surfaces: Candle Soot as a Promising Class of Nanoparticles for Self-cleaning and Oil–Water Separation Applications

Abstract A novel, versatile, environment-friendly, and economical method was developed to fabricate functional superhydrophobic surfaces on various substrates, including wood, bamboo, cotton, filter paper, sponge, glass, textile, and copper. This method involves synthesizing a two-component modifier solution consisting of SiO2 nanoparticles combination with poly(methylhydrogen)siloxane (PMHS) modification. The superhydrophobicity of the coated surfaces was created by PMHS combined with SiO2 nanoparticles to construct a rough hierarchical structure on the substrate surface. As a result, all superhydrophobic surfaces were maintained under an indoor environment and relative humidity (RH) of 50% for 30 days. Furthermore, the superhydrophobic surfaces were also maintained at environmental conditions of minus 20℃ for 24 hours. It was also confirmed that these surfaces exhibited excellent self-cleaning, oil/water separation, and elimination of underwater oil properties. The method for fabricating superhydrophobic materials proposed in this study will have great application potential in preparing large-scale superhydrophobic surfaces for use in ancient building protection.

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Synthesis of Durable Superhydrophobic Coating and Its Applications in Oil/Water Separation

Science of Advanced Materials ◽

10.1166/sam.2020.3690 ◽

2020 ◽

Vol 12 (5) ◽

pp. 676-684 ◽

Cited By ~ 3

Author(s):

Guo-Qiang Xi ◽

Jun-Feng Li ◽

Hui Deng ◽

Ming-Guo Ma

Keyword(s):

Water Resistance ◽

Collection Efficiency ◽

Superhydrophobic Surfaces ◽

Superhydrophobic Coating ◽

Water Contact ◽

Water Separation ◽

Potential Applications ◽

Oil Water Separation ◽

Oil Water ◽

Self Cleaning

Superhydrophobic surfaces have received enormous attention thanking to their potential applications in the areas of anti-icing, anti-contamination, and oil/water separation. Herein, we have successfully prepared superhydrophobic surfaces, which were synthesized by using the polydimethylsiloxane (PDMS) as adhesive and the magnesium palmitate (Mg-P) were evently coated to form roughness on the surfaces of glass, textile, stainless steel mesh, and paper. The as-fabricated superhydrophobic surfaces possessed excellent water-resistance, self-cleaning properties, durability, and robustness. Remarkably, in the actual oil/water separation, the water contact angle and oil collection efficiency of the superhydrophobic mesh were still more than 150° and 91% even after separation over 10 cycles, respectively. Thus, the superhydrophobic coating has applications potential in self-cleaning, anti-contamination, and oil/water separation fields.

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Facile fabrication of raspberry-like composite microspheres for the construction of superhydrophobic films and applications in highly efficient oil–water separation

RSC Advances ◽

10.1039/c7ra07250c ◽

2017 ◽

Vol 7 (63) ◽

pp. 39471-39479 ◽

Cited By ~ 30

Author(s):

Mingguang Yu ◽

Qing Wang ◽

Min Zhang ◽

Qianjun Deng ◽

Dongchu Chen

Keyword(s):

Superhydrophobic Surfaces ◽

Synthetic Route ◽

Water Separation ◽

Lotus Effect ◽

Highly Efficient ◽

Composite Microspheres ◽

Oil Water Separation ◽

Facile Fabrication ◽

Oil Water

Inspired by the “lotus effect”, we proposed a facile synthetic route toward raspberry-like PS@SiO2 microspheres, which further lead to superhydrophobic surfaces.

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Facile fabrication of environmentally friendly bio-based superhydrophobic surfaces via UV-polymerization for self-cleaning and high efficient oil/water separation

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2019.105346 ◽

2019 ◽

Vol 137 ◽

pp. 105346 ◽

Cited By ~ 1

Author(s):

Qianqian Shang ◽

Jianqiang Chen ◽

Chengguo Liu ◽

Yun Hu ◽

Lihong Hu ◽

...

Keyword(s):

Environmentally Friendly ◽

Superhydrophobic Surfaces ◽

Water Separation ◽

High Efficient ◽

Oil Water Separation ◽

Facile Fabrication ◽

Oil Water ◽

Self Cleaning

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Adsorption and superficial transport of oil on biological and bionic superhydrophobic surfaces: a novel technique for oil–water separation

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0447 ◽

2020 ◽

Vol 378 (2167) ◽

pp. 20190447

Author(s):

W. Barthlott ◽

M. Moosmann ◽

I. Noll ◽

M. Akdere ◽

J. Wagner ◽

...

Keyword(s):

Oil Spills ◽

Superhydrophobic Surfaces ◽

Contaminated Water ◽

Theme Issue ◽

External Energy ◽

Water Separation ◽

Lotus Effect ◽

Oil Water Separation ◽

Air Layers ◽

Oil Water

Superhydrophobicity is a physical feature of surfaces occurring in many organisms and has been applied (e.g. lotus effect) in bionic technical applications. Some aquatic species are able to maintain persistent air layers under water ( Salvinia effect) and thus become increasingly interesting for drag reduction and other ‘bioinspired’ applications. However, another feature of superhydrophobic surfaces, i.e. the adsorption (not absorption) and subsequent superficial transportation and desorption capability for oil, has been neglected. Intense research is currently being carried out on oil-absorbing bulk materials like sponges, focusing on oleophilic surfaces and meshes to build membranes for oil–water separation. This requires an active pumping of oil–water mixtures onto or through the surface. Here, we present a novel passive, self-driven technology to remove oil from water surfaces. The oil is adsorbed onto a superhydrophobic material (e.g. textiles) and transported on its surface. Vertical and horizontal transportation is possible above or below the oil-contaminated water surface. The transfer in a bioinspired novel bionic oil adsorber is described. The oil is transported into a container and thus removed from the surface. Prototypes have proven to be an efficient and environmentally friendly technology to clean oil spills from water without chemicals or external energy supply. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 3)’.

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Surface engineering with microstructured gel networks for superwetting membranes

Journal of Materials Chemistry A ◽

10.1039/d0ta12278e ◽

2021 ◽

Author(s):

Yuandong Jia ◽

Kecheng Guan ◽

Pengfei Zhang ◽

Qin Shen ◽

Shengyao Wang ◽

...

Keyword(s):

Surface Engineering ◽

Water Harvesting ◽

Structure And Properties ◽

Water Separation ◽

Distinct Structure ◽

Oil Water Separation ◽

Oil Water ◽

Self Cleaning

Superwetting surfaces have several applications, such as self-cleaning, anti-fouling, anti-corrosion, water harvesting, and oil–water separation, owing to their distinct structure and properties. Hydrogel-based coatings are particularly attractive owing to their...

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