Superhydrophobic PVC/SiO2 Coating for Self-Cleaning Application

A lotus leaf like self-cleaning superhydrophobic coating has high demand in industrial applications. Such coatings are prepared by alternative dip and spray deposition techniques. A layer of polyvinyl chloride is applied on glass substrate by dip coating and then spray coated a suspension of hydrophobic silica nanoparticles at substrate temperature of 50 °C. This coating procedure is repeated for three times to achieve rough surface morphology which exhibits a water contact angle of 169 ± 2° and sliding angle of 6°. The superhydrophobic state of the coating is still preserved when water volume of 1.2 L is used to impact the water drops on coating surface. The stability of the wetting state of the coating is analyzed against the water jet, adhesive tape and sandpaper abrasion tests. The prepared superhydrophobic coating strongly repelled the muddy water suggesting its importance in self-cleaning applications.This work was 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

Recent developments in air-trapped superhydrophobic and liquid-infused slippery surfaces for anti-icing application

Anti-icing coating is one of the recent hot topics in industrial applications as well as from the academic viewpoint. Icing is one of the major problem on various substrates such as glass windows in buildings as well as vehicles, solar panels, wind turbine blades, airplanes, transmission lines, power towers, traffic signals, off-shore oil platforms, telecommunication antennas, and many others. Ice accumulation can significantly reduce the performance of the substrates and results in poor visibility. Recently, considerable attention is being paid on the naturally inspired superhydrophobic/icephobic surfaces by mimicking its surface property for the development of artificial self-cleaning superhydrophobic and ice-phobic surfaces. A good example is the lotus leaf surface where hierarchical micro and nano-scale rough structure covered by low surface energy coating layer on the leaf can repel water droplets and prevent ice accumulation. On superhydrophobic surfaces, impacting and condensed water droplets rolled off before freezing at subzero temperature. On the other hand, in slippery liquid-infused porous surface (SLIPS), the air pockets are replaced by immiscible lubricant film which can easily remove the accumulated ice without any damage to the surface. In this review article, we describe the recent progress in passive anti-icing coating materials and methodologies. Metal substrates, polymers, and nanoparticles/polymer composites are playing the major role in the development of anti-icing surface. So, the main goal of this review articles deals with the development of various synthetic routes of superhydrophobic anti-icing coating materials from metal substrates, polymers, and nanoparticles/polymer composites. In addition, the role of SLIPS in anti-icing coating and their use are also discussed. - 2019 Elsevier B.V.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 ( 21776061 ) and ( 21950410531 ), Foundation of Henan province ( 182102410090 ). S. Nagappan and C. S. Ha thanks to the financial support from the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science and ICT, Korea ( NRF2017R1A2B3012961 ); Brain Korea 21 Plus Program ( 21A2013800002 ).Scopu

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

Oil-Water Separation by ZnO-Based Superhydrophobic PU Sponges

Continuous oil–water separation is not only an important topic for scientific research but also for practical applications to clean oil from industrial oily wastewater and oil-spill pollution. In this work, polyurethane sponges are coated by ZnO using dip coating technique. ZnO-coated sponges are modified by stearic acid to achieve superhydrophobicity. The ZnO-coated sponges exhibit water contact angle ≈165° and oil contact angle ≈0°. The prepared superhydrophobic sponge is sustained in oil–water separation and in separation of oil–hot water mixture. Also the wetting properties of the sponge are stable in mechanical test like cutting and twisting. Stearic acid modified ZnO-coated sponge holds good promise for oil-spill cleanup as well as oil/water separation from harsh environments.This work was 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

Superhydrophobic Leaf Mesh Decorated with SiO2 Nanoparticle-Polystyrene Nanocomposite for Oil-Water Separation

Here, we report a novel and simple approach to fabricate crater-like superhydrophobic leaf mesh for oil-water separation. Nanocomposite of SiO2 and polystyrene (SiO2-PS) deposited on a naturally dried Tectona grandis leaf mesh showed excellent superhydrophobic and superoleophilic properties. The obtained multifunctional leaf mesh exhibited fast separation of various oils like petrol, kerosene, diesel, coconut oil from oil-water mixtures with separation efficiency greater than 95%, which lasts for more than 18 separation cycles. The prepared material can be used efficiently for the oil-water mixture separation for any oil with absolute viscosity of less than 55 cP.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

Spray Deposition of PDMS/Candle Soot NPs Composite for Self-Cleaning Superhydrophobic Coating

The preparation of superhydrophobic coating using cheap candle soot nanoparticles (CS NPs) collected from candle flame is a very novel research topic. A less than 30 nm sized candle soot particles are collected by passing through stainless steel mesh of pore size ̴30 nm. An optimum suspension of CS NPs and polydimethylsiloxane (PDMS) in chloroform is sprayed on clean glass substrate and dried at 100°C for 1 hour. The coating surface with water contact angle ̴173° and rolling angle ̴ 4° is achieved by spraying suspension of 100 mg CS NPs and 0.3 mL PDMS in chloroform. The stability of superhydrophobic coating is studied by finger-wiping, water jet hitting, water dripping, adhesive tape, and sandpaper abrasion test. Result showed that the coatings prepared with an optimum 100 mg CS NPs in suspension are stable under water jet hitting and water dripping test. The superhydrophobicity is destroyed for four cycles of adhesive tape peeling and seven cycles of sandpaper abrasion tests. The coated substrate showed good self-cleaning performance. The high water repellent and self-cleaning property of the prepared coating can be adopted 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. The authors greatly appreciate the support of the National Natural Science Foundation of China (21950410531).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

Superhydrophobic Coating Using TiO2 NPs/PMHS Composite for Self-Cleaning Application

In the present research work, spray deposition technique is adopted for the fabrication of superhydrophobic coating on glass slide using TiO2 nanoparticles and polymethylhydrosyloxane (PMHS) composite. The prepared superhydrophobic coating revealed hierarchical surface morphology due to different micro and nanoscaled grains of TiO2 NPs/PMHS composite. The water drops hardly stay on the superhydrophobic coating and roll off the surface at sliding angle of 6° due to high water contact angle of 163 ± 2°. As a result, the prepared superhydrophobic coating revealed excellent self-cleaning performance. To evaluate the mechanical durability the prepared superhydrophobic coating, the coating surface is exposed to water jet, water drop impact, adhesive tape peeling, and sandpaper abrasion tests. This coating approach can be applied to the substrates of any size and shape.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