Investigations Into Superhydrophobicity of a Soot Surface Attributed to Nano-Asperities

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Rahul Ramachandran ◽  
Madhu Seetharaman ◽  
N. N. Sharma
Keyword(s):  
Superhydrophobic Surface ◽  
Low Cost ◽  
Water Repellency ◽  
Cost Effective ◽  
High Water ◽  
Work Of Adhesion ◽  
Water Contact ◽  
Glass Substrates ◽  
Micrometer Scale ◽  
Scale Roughness

Superhydrophobicity in nature is the result of multiscale (hierarchical) roughness which consists of nano-asperities superimposed on micrometer scale roughness. A low-cost superhydrophobic surface was prepared by depositing soot on Vaseline coated glass substrates. The surface was rapidly prepared without any sophisticated fabrication facilities. The surface exhibited a remarkably high water contact angle of 161 deg and a roll-off angle of 3 deg. Atomic force microscopy (AFM) of the surface was done which revealed a very rough surface. The roughness features with nano-asperities superimposed on micrometer scale roughness enhance the water repellency. The micrometer scale peaks on the surface support the water droplet in a Cassie–Baxter state with the nano-asperities sheltering a composite interface below the droplet. The work of adhesion for the surface was also low at 18 nJ. The study will enable easy preparation of a cost effective superhydrophobic surface.

scholarly journals Improving the Hydrophobicity of ZnO by PTFE Incorporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Meenu Srivastava ◽  
Bharathi Bai J. Basu ◽  
K. S. Rajam
Keyword(s):  
Thermal Treatment ◽  
Stearic Acid ◽  
Superhydrophobic Surface ◽  
Cost Effective ◽  
Electrical Energy ◽  
High Water ◽  
Superhydrophobic Coating ◽  
Water Contact ◽  
Low Surface Energy ◽  
Effective Manner

The objective of the present study is to obtain a zinc oxide- (ZnO-) based superhydrophobic surface in a simple and cost-effective manner. Chemical immersion deposition being simple and economical has been adopted to develop modified ZnO coating on glass substrate. Several modifications of ZnO like treatment with alkanoic acid (stearic acid) and fluoroalkylsilane to tune the surface wettability (hydrophobicity) were attempted. The effect of thermal treatment on the hydrophobic performance was also studied. It was observed that thermal treatment at 70°C for 16 hrs followed by immersion in stearic acid resulted in high water contact angle (WCA), that is, a superhydrophobic surface. Thus, a modified ZnO superhydrophobic surface involves the consumption of large amount of electrical energy and time. Hence, the alternate involved the incorporation of low surface energy fluoropolymer polytetrafluoroethylene (PTFE) in the ZnO coating. The immersion deposited ZnO-PTFE composite coating on modification with either stearic acid or fluoroalkylsilane resulted in a better superhydrophobic surface. The coatings were characterized using Scanning Electron Microscope (SEM) for the surface morphology. It was found that microstructure of the coating was influenced by the additives employed. A flower-like morphology comprising of needle-like structure arranged in a radial manner was exhibited by the superhydrophobic coating.

scholarly journals Superhydrophobicity and Durability in Recyclable Polymers Coating

2021 ◽  
Vol 13 (15) ◽  
pp. 8244
Author(s):  
Francesca Cirisano ◽  
Michele Ferrari
Keyword(s):  
Thermal Treatment ◽  
Superhydrophobic Surface ◽  
Low Cost ◽  
Spray Coating ◽  
Large Area ◽  
Average Roughness ◽  
Water Contact ◽  
Alkaline Environments ◽  
Fine Control ◽  
Recycle And Reuse

Highly hydrophobic and superhydrophobic materials obtained from recycled polymers represent an interesting challenge to recycle and reuse advanced performance materials after their first life. In this article, we present a simple and low-cost method to fabricate a superhydrophobic surface by employing polytetrafluoroethylene (PTFE) powder in polystyrene (PS) dispersion. With respect to the literature, the superhydrophobic surface (SHS) was prepared by utilizing a spray- coating technique at room temperature, a glass substrate without any further modification or thermal treatment, and which can be applied onto a large area and on to any type of material with some degree of fine control over the wettability properties. The prepared surface showed superhydrophobic behavior with a water contact angle (CA) of 170°; furthermore, the coating was characterized with different techniques, such as a 3D confocal profilometer, to measure the average roughness of the coating, and scanning electron microscopy (SEM) to characterize the surface morphology. In addition, the durability of SH coating was investigated by a long-water impact test (raining test), thermal treatment at high temperature, an abrasion test, and in acidic and alkaline environments. The present study may suggest an easy and scalable method to produce SHS PS/PTFE films that may find implementation in various fields.

scholarly journals Ultralow-temperature-driven water-based sorption refrigeration enabled by low-cost zeolite-like porous aluminophosphate

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhangli Liu ◽  
Jiaxing Xu ◽  
Min Xu ◽  
Caifeng Huang ◽  
Ruzhu Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Water Sorption ◽  
High Performance ◽  
Global Climate ◽  
Low Cost ◽  
Cost Effective ◽  
High Water ◽  
Coefficient Of Performance ◽  
High Efficient ◽  
Water Based

AbstractThermally driven water-based sorption refrigeration is considered a promising strategy to realize near-zero-carbon cooling applications by addressing the urgent global climate challenge caused by conventional chlorofluorocarbon (CFC) refrigerants. However, developing cost-effective and high-performance water-sorption porous materials driven by low-temperature thermal energy is still a significant challenge. Here, we propose a zeolite-like aluminophosphate with SFO topology (EMM-8) for water-sorption-driven refrigeration. The EMM-8 is characterized by 12-membered ring channels with large accessible pore volume and exhibits high water uptake of 0.28 g·g−1 at P/P0 = 0.2, low-temperature regeneration of 65 °C, fast adsorption kinetics, remarkable hydrothermal stability, and scalable fabrication. Importantly, the water-sorption-based chiller with EMM-8 shows the potential of achieving a record coefficient of performance (COP) of 0.85 at an ultralow-driven temperature of 63 °C. The working performance makes EMM-8 a practical alternative to realize high-efficient ultra-low-temperature-driven refrigeration.

Toward Easily Enlarged Superhydrophobic Copper Surfaces with Enhanced Corrosion Resistance, Excellent Self-Cleaning and Anti-Icing Performance by a Facile Method

2020 ◽  
Vol 20 (10) ◽  
pp. 6317-6325 ◽  
Author(s):  
Xueting Shi ◽  
Libin Zhao ◽  
Jing Wang ◽  
Libang Feng
Keyword(s):  
Corrosion Resistance ◽  
Superhydrophobic Surface ◽  
Cost Effective ◽  
Copper Plate ◽  
Plate Surface ◽  
Water Contact ◽  
Copper Surfaces ◽  
Self Cleaning ◽  
Water Repellence

This work reports a facile method for fabricating superhydrophobic surface on copper plate by AgNO3 treatment and dodecyl mercaptan modification. The as-prepared superhydrophobic copper plate presents hierarchical and rough morphology composed of nanosheets and nanoparticleformed matrix. Meanwhile, long alkyl chains are assembled onto the rough surface successfully. Consequently, the copper plate is endowed with excellent superhydrophobic performance with a water contact angle of 156.8° and a rolling angle of ca. 3°. Moreover, the superhydrophobicity has long-term durability and excellent stability. Grounded on the strong water repellence, the resultant superhydrophobic copper plate surface exhibits multi-functions. The excellent performance can be well explained by “Cushion effect” and Capillary phenomena. As a result, water and corrosive species can be prevented from contacting with the copper plate surface, and contaminants can be taken away easily by the rolling water droplets. Meanwhile, the icing process of water is delayed on the superhydrophobic surface. Therefore, the superhydrophobic copper is endued with enhanced corrosion resistance, excellent self-cleaning and anti-icing performance. We believe that this facile method provides a simple and cost-effective process to improve the properties of copper plate, and which may see practical application of the superhydrophobic materials.

scholarly journals Superhydrophobic Surface with Gamma Irradiation Resistance and Self-Cleaning Effect in Air and Oil

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
Yan Zhang ◽  
Jing Zhang ◽  
Yujian Liu
Keyword(s):  
Superhydrophobic Surface ◽  
Water Repellency ◽  
Sio2 Nanoparticles ◽  
Superior Performance ◽  
Sliding Angle ◽  
Water Contact ◽  
Composite Surface ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Dirt Removal

A superhydrophobic surface was synthesized by a combination of an epoxy/polymethylphenylsiloxane matrix and dual-scale morphology of silica (SiO2) nanoparticles. When the amount of SiO2 reached 30 wt.%, the as-prepared surface showed a high static water contact angle (WCA) of 154° and a low sliding angle (SA) of 5°, excellent water repellency, and dirt-removal effects both in air and oil (hexamethylene). Even after exposure to as high as a 12.30 Mrad dose of gamma-rays, the composite surface still maintained its superior performance.

scholarly journals Superhydrophobic Surface Fabricated on Carbon Steel Substrate by Zinc Electrodeposition for Prevention of Corrosion

2018 ◽  
Vol 38 ◽  
pp. 02024 ◽  
Author(s):  
Liping Wang ◽  
Lei Zhuang ◽  
Gang Chen ◽  
Dong Leng ◽  
Jian wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Superhydrophobic Surface ◽  
Steel Substrate ◽  
Low Cost ◽  
Energy Dispersive Spectrometer ◽  
Water Contact ◽  
Zinc Electrodeposition ◽  
Excellent Corrosion Resistance ◽  
Polarization Test

A facile, low cost, and relatively environmental friendly method was presented for the fabrication of superhydrophobic surface on carbon steel substrate. The superhydrophobic surface was obtained by zinc electrodeposition and chemical modification with ethanolic stearic acid. The wettability of the superhydrophobic surface was measured by a water contact angle (WCA) with a highest value of 155.7°. The morphology of the fabricated film was characterized by scanning electron microscopy (SEM). The chemical composition of the fabricated surface was analysed by energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR), respectively. The corrosion resistance of the carbon steel substrate was measured by potentiodynamic polarization test in 3.5 wt% NaCl solution. The electrochemical measurements show excellent corrosion resistance, which may have promising applications in anticorrosion of carbon steel.

A Two-Step Method to Prepare Stable Superhydrophobic Surface on Steel Substrates

2012 ◽  
Vol 463-464 ◽  
pp. 349-353 ◽  
Author(s):  
Feng Guo ◽  
Xun Jia Su ◽  
Gen Liang Hou ◽  
Zhao Hui Liu ◽  
Hai Peng Jia
Keyword(s):  
Contact Angle ◽  
Superhydrophobic Surface ◽  
Low Cost ◽  
Superhydrophobic Surfaces ◽  
Step Method ◽  
Water Contact ◽  
Lotus Leaf ◽  
Nanoscale Particles ◽  
Steel Substrates

Superhydrophobic surfaces have been a hot topic during the last decade owing to their great potential in widely application. In this work, we report on a facile and low-cost two-step method to fabricate superhydrophobic surface on steel substrates. The as-obtained surface shows an interesting hierarchical structure composed of microscale flowerlike cluster and nanoscale particles, which is similar to that of a lotus leaf. After further modification with stearic acid, the resultant surface exhibits remarkable superhydrophobic properties. The water contact angle is as high as 155°. Moreover, the superhydrophobic properties are long-term stable.

scholarly journals 698 PB 306 WETTABILITY AND SURFACE TENSION OF FRUIT SURFACES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 533a-533 ◽  
Author(s):  
L. Cisneros-Zevallos ◽  
M. E. Saltveit ◽  
J. M Krochta
Keyword(s):  
Surface Tension ◽  
Water Repellency ◽  
High Water ◽  
Contact Angles ◽  
Stone Fruits ◽  
Water Contact ◽  
Wetting Behavior ◽  
Apple Cultivars ◽  
Chemical Groups ◽  
Apple Fruits

Nettability is an important factor to be considered in postharvest treatments such as washing, aqueous dippings, coatings, etc. Pome fruits (ten apple and four pear cultivars) and stone fruits (nectarine and plums) were evaluated for wetting behavior and surface tension at room temperature. Nettability was assessed by measuring contact angles of water. Surface tension was calculated by measuring contact angles of methylene iodide and water or by a series of pure surfactants using Zisman's method. Wetting behavior on apple fruits depended on cultivar, with water contact angles ranging from 75° to 131°. For pear fruits, wetting also depended on cultivar. Calculated surface tensions of pear fruits were in general higher than most apple cultivars tested. In stone fruits, plums presented a high water-repellency with a contact angle of 137°. The wetting of fruit surfaces seems to be governed by the nature of the chemical groups exposed on the surface of the cuticle and also by the surface roughness, as evidenced by tire high values of some contact angles.

scholarly journals Fabrication and Characterization of Superhydrophobic Graphene/Titanium Dioxide Nanoparticles Composite

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 122
Author(s):  
Xun Hui Wu ◽  
Yoon Yee Then
Keyword(s):  
Contact Angle ◽  
Titanium Dioxide ◽  
Water Contact Angle ◽  
Medical Devices ◽  
Superhydrophobic Surface ◽  
Cost Effective ◽  
Tio2 Coating ◽  
Hybrid Nanoparticles ◽  
Poly Lactic Acid ◽  
Water Contact

Materials with superhydrophobic surfaces have received vast attention in various industries due to their valuable properties, such as their self-cleaning and antifouling effects. These promising superhydrophobic properties are taken into high priority, particularly for medical devices and applications. The development of an ideal superhydrophobic surface is a challenging task and is constantly progressing. Various strategies have been introduced; however, a minority of them are cost-effective. This work presents a facile fabrication of the superhydrophobic surface by using graphene and titanium dioxide (TiO2) nanoparticles. The graphene and TiO2 hybrid nanoparticles are dip-coated on a biodegradable thermoplastic poly(lactic acid) (PLA) substrate. The thermoplastic PLA is approved by the Food and Drug Administration (FDA), and is widely utilized in medical devices. The graphene/TiO2 coating is substantiated to transform the hydrophilic PLA film into superhydrophobic biomaterials that can help to reduce hazardous medical-device complications. The surface wettability of the graphene/TiO2 nanoparticle-coated PLA surface was evaluated by measuring the apparent water contact angle. The surface chemical composition and surface morphology were analyzed via Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The graphene/TiO2-coated PLA film achieved superhydrophobic properties by demonstrating a water contact angle greater than 150°. The water contact angle of the graphene/TiO2 coating increased along with the concentration of the nanoparticles and the ratio of TiO2 to graphene. Moreover, the graphene/TiO2 coating exhibited excellent durability, whereby the contact angle of the coated surface remained unchanged after water immersion for 24 h. The duration of the effectiveness of the superhydrophobic coating suggests its suitability for medical devices, for which a short duration of administration is involved. This study reports an easy-to-replicate and cost-effective method for fabricating superhydrophobic graphene/TiO2-coated surfaces, which additionally substantiates a potential solution for the manufacturing of biomaterials in the future.

scholarly journals Estradiol Removal by Adsorptive Coating of a Microfiltration Membrane

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 99
Author(s):  
Zahra Niavarani ◽  
Daniel Breite ◽  
Andrea Prager ◽  
Bernd Abel ◽  
Agnes Schulze
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Low Cost ◽  
High Water ◽  
Adsorption Properties ◽  
Experimental Conditions ◽  
Water Contact ◽  
Endocrine Disrupting Chemical ◽  
Pes Membrane

This work demonstrates the enhancement of the adsorption properties of polyethersulfone (PES) microfiltration membranes for 17β-estradiol (E2) from water. This compound represents a highly potent endocrine-disrupting chemical (EDC). The PES membranes were modified with a hydrophilic coating functionalized by amide groups. The modification was performed by the interfacial reaction between hexamethylenediamine (HMD) or piperazine (PIP) as the amine monomer and trimesoyl chloride (TMC) or adipoyl chloride (ADC) as the acid monomer on the surface of the membrane using electron beam irradiation. The modified membranes and the untreated PES membrane were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), water permeance measurements, water contact angle measurements, and adsorption experiments. Furthermore, the effects of simultaneous changes in four modification parameters: amine monomer types (HMD or PIP), acid monomer types (TMC or ADC), irradiation dosage (150 or 200 kGy), and the addition of toluene as a swelling agent, on the E2 adsorption capacity were investigated. The results showed that the adsorption capacities of modified PES membranes toward E2 are >60%, while the unmodified PES membrane had an adsorption capacity up to 30% for E2 under similar experimental conditions, i.e., an enhancement of a factor of 2. Next to the superior adsorption properties, the modified PES membranes maintain high water permeability and no pore blockage was observed. The highlighted results pave the way to develop efficient low-cost, stable, and high-performance adsorber membranes.

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