Self - cleaning superhydrophobic coatings: Potential industrial applications

Many technologies have surfaced through careful observation and investigation of unusual features of various species found in Nature. Among which, the remarkable non-wetting properties of lotus leaf has hugely occupied the minds of students, researchers and industrialists from last two decades. Due to high contact angle (>150), water drops readily roll off the lotus leaf surface compiling dirt particles. This self-cleaning lotus effect has found huge attention in daily life. Many surfaces in day-to-day life eventually get contaminated due to the accumulation of dust/dirt or through air pollution. A huge amount of money, labor and energy is wasted in their restoration. The self-cleaning superhydrophobic coating is one of the best options for this problem. In this study, the suspension of hydrophobic silica nanoparticles was dip and/or spray coated on the body of motorcycle, building wall, mini boat, solar cell panel, window glass, cotton shirt, fabric shoes, paper (currency notes), metal, wood, sponges, plastic and marble. Every coated substrate exhibited superhydrophobicity with water contact angle nearly 160 and sliding angle less than 6 . The self-cleaning performance of the superhydrophobic coating applied on various substrates was thoroughly evaluated. The specific purpose of this article is to explore the possible industrial applications of self-cleaning superhydrophobic coatings.This work is financially supported by DST-INSPIRE Faculty Scheme, Department of Science and Technology (DST), Govt. of India [ DST/INSPIRE/04/2015/000281 ]. SSL acknowledges financial assistance from the Henan University, Kaifeng, P. R. China . We also greatly appreciate the support of the National Natural Science Foundation of China ( 21576071 , 21776061 ), Foundation of Henan Educational Committee ( 17A150023 ). Authors are thankful to Mr. Tukaram Sannakke, Dept. of English, Raje Ramrao College, Jath, India for editing a draft of this manuscript.Scopu

Sawdust-based superhydrophobic pellets for efficient oil-water separation

Severe water pollution by means of oil is the major issue worldwide. Emerging materials like superhydrophobic surfaces have shown immense potential to control this issue. Herein we utilized low-cost Sawdust-Polystyrene (SD ? PS) composite and developed a facile strategy to prepare a free-standing superhydrophobic pellet for efficient oil-water separation. More importantly, the simple recovery of the absorbed oil is feasible. To achieve crack-free, regular and robust superhydrophobic SD ? PS pellet, the concentration of polystyrene, the quantity of sawdust in polymer solution and thickness of the pellet was optimised. The surface morphology analysis confirmed an adequate binding between sawdust and polystyrene in composite structure with formation of micro-voids less than 100 ?m that facilitated efficient oil-water separation. The superhydrophobic pellet exhibited oil-water separation efficiency higher than 90% for the oils and organic liquids like hexane, kerosene, diesel and coconut oil with excellent separation cycles around 30. The mechanically durable superhydrophobic SD ? PS pellet could separate oil from muddy as well as warm water, which are more suitable for industrial applications.This work is financially supported by DST ? INSPIRE Faculty Scheme, Department of Science and Technology (DST), Govt. of India. [ DST/INSPIRE/04/2015/000281 ]. SSL acknowledges financial assistance from the Henan University, Kaifeng, P. R. China. We greatly appreciate the support of the National Natural Science Foundation of China ( 21950410531 ). We also thank Dr. Daibing Luo from Analytical and Testing Center of Sichuan University, China, for the analysis.Scopu

Superhydrophobic PU Sponge Modified by Hydrophobic Silica NPs-Polystyrene Nanocomposite for Oil-Water Separation

In this study, the hydrophobic silica nanoparticles (NPs) are synthesized by simple sol–gel processing of polymethylhydrosiloxane (PMHS). The nanocomposite solution is prepared by adding hydrophobic silica NPs in polystyrene solution and applied on the skeleton of polyurethane sponge by simple immersion-drying process. The as-prepared sponges exhibited superhydrophobic property with water contact angle 161° and oil contact angle nearly 0° and can separate oil from oil–water and oil–muddy water mixture. The superhydrophobic sponge has sustainable anti-wetting property under cross sectional cutting, pressing and twisting, and different pH environment. Such superhydrophobic sponge is suitable for practical application on a large scale.This work is financially supported by DST ? INSPIRE Faculty Scheme, Department of Science and Technology (DST), Govt. of India. [DST/INSPIRE/04/2015/000281]. SSL acknowledges financial assistance from the Henan University, Kaifeng, P. R. China. The authors greatly appreciate the support of the National Natural Science Foundation of China (21950410531).Scopu