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 Fabrication of Superhydrophobic Nanocomposite Coatings Using Polytetrafluoroethylene and Silica Nanoparticles

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Bharathibai J. Basu ◽  
V. Dinesh Kumar
Keyword(s):  
Cost Effective ◽  
High Water ◽  
Nanocomposite Coatings ◽  
Sliding Angle ◽  
Electron Microscopic ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Low Surface Energy ◽  
Hydrophobically Modified ◽  
Superhydrophobic Property

Superhydrophobic nanocomposite coatings were fabricated by incorporating hydrophobically modified silica (HMS) nanoparticles in polytetrafluoroethylene (PTFE) emulsion. Hydrophobicity of the coating was dependent on the concentration of HMS. Coatings containing optimum amounts of PTFE and HMS exhibited superhydrophobic property with high water contact angle (WCA) of 165∘ and low sliding angle <2∘. Scanning electron microscopic (SEM) studies have shown a binary surface topography composed of microbumps and nanoscale granules. The synergistic effect of the micro-nano-binary structure and low surface energy of PTFE was responsible for the superhydrophobicity of the coating. The method is simple and cost-effective and can be used for preparing self-cleaning superhydrophobic coatings on large areas of different kinds of substrates like glass, metal, and composites.

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 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 Fabrication and Evaluation of Nano-TiO2 Superhydrophobic Coating on Asphalt Pavement

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 211
Author(s):  
Hongfeng Li ◽  
Xiangwen Lin ◽  
Hongguang Wang
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Waterborne Polyurethane ◽  
Superhydrophobic Coating ◽  
Nano Tio2 ◽  
Sem Image ◽  
Low Surface Energy ◽  
Water Damage

In order to address water damage of asphalt pavement, reduce the occurrence of water-related potholes, deformation, and other diseases, and improve the performance and service life of the pavement, a nano-TiO2 superhydrophobic coating (PSC) on asphalt pavement was prepared from waterborne polyurethane and nano-TiO2 modified by stearic acid. FT-IR measured stearic acid successfully modified low surface energy substance on the surface of nano-TiO2. The SEM image shows that the PSC has a rough surface structure. The contact angle and rolling angle of the PSC in the contact angle test are 153.5° and 4.7°, respectively. PSC has a super-hydrophobic ability, which can improve the water stability of the asphalt mixture. Although the texture depth and pendulum value have been reduced by 2.5% and 4.4%, respectively, they all comply with the standard requirements. After the abrasion resistance test, the PSC coating still has a certain hydrophobic ability. These results surface PSC coating can effectively reduce water damage on asphalt pavement, and has considerable application value.

Preparation and Properties Fluoralkylpolysiloxane Modified Polyurethane Films

2009 ◽  
Vol 620-622 ◽  
pp. 741-744 ◽  
Author(s):  
Rui Weng ◽  
Chong Rui Wang ◽  
Lian Meng Zhang ◽  
Shui Ping Wang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Silicone Oil ◽  
Soft Segment ◽  
High Water ◽  
Water Contact ◽  
Sulfuryl Fluoride ◽  
Low Surface Energy ◽  
End Capping ◽  
Amino Silicone

Fluoralkylpolysiloxane modified Polyurethane (FSPU) films with high water contact angle (CA) were prepared. fluoralkylpolysiloxane was obtained using perfluoro octyl sulfuryl fluoride and terminal amino-silicone oil as reactants. Then, the isocyanate end capped PU prepolymer was synthesized by reacting isocyanate with a soft segment mixed by active amino-end-capping fluoralkylpolysiloxane and polyether glycol. The fluoralkylpolysiloxane modified PU films were obtained after the PU prepolymer was cured by 3,3 '- dichloro -4,4' – amino - diphenyl methane (MOCA). The results showed that the modified polyurethane with 10% (mass fraction) PFATPS had a good compatibility, low surface energy, surface water contact angle and surface oil contact angle was improved by 49° and 37° respectively, and heat resistance, water resistance was apparently improved.

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.

Fabrication of Superhydrophobic Surfaces on Copper Foil with Stearic Acid

2011 ◽  
Vol 295-297 ◽  
pp. 921-924 ◽  
Author(s):  
Li Bo Wang ◽  
Yang Lu ◽  
Xin Xin Cao
Keyword(s):  
Stearic Acid ◽  
Photoelectron Spectroscopy ◽  
Pure Copper ◽  
Copper Substrate ◽  
High Water ◽  
Random Pattern ◽  
Mixed Solution ◽  
Sem Images ◽  
Water Contact ◽  
Porous Architecture

Superhydrophobic surface was prepared by hydrothermal method on copper substrate via immersing the clean pure copper substrate into the mixed solution of H2O2and C2H5OH, and then the substrate was heated at 100°C for 1.5 h, followed by modifying with stearic acid. The product was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. The wettability of the products was also investigated. It was found that the as-prepared surface had a high water contact angle of about 153°. SEM images of the film showed that many irregular micro-nano sheets distributed on the surface in a random pattern. The special porous architecture, with the low surface energy leads to the surface superhydrophobicity.

Improving the Mechanical Durability of Superhydrophobic Coating by Deposition on to a Mesh Structure

2017 ◽  
Author(s):  
Weihua Hu ◽  
De-Quan Yang ◽  
Edward Sacher
Keyword(s):  
Surface Energy ◽  
Superhydrophobic Surface ◽  
Impact Resistance ◽  
Superhydrophobic Surfaces ◽  
Superhydrophobic Coating ◽  
Mesh Structure ◽  
Mechanical Abrasion ◽  
Low Surface Energy ◽  
Jet Impact ◽  
Mechanical Durability

<p>Superhydrophobic surfaces (SHSs) require a combination of a rough nano- or microscale structured surface topography and a low surface energy. However, its superydrophobicity is easily lost, even under relatively mild mechanical abrasion, when the surface is mechanically weak. Here, we develop a method that significantly increases the mechanical durability of a superhydrophobic surface, by introducing a mesh layer beneath the superhydrophobic layer. The hardness, abrasion distance, flexibility and water-jet impact resistance all increase for the commercially available Ultra-ever Dry superhydrophobic coating. This is attributed to the increased mechanical durability offered by the mesh, whose construction not only increases the porosity of the SHS coating but acts as a third, larger structure, so that the superhydrophobic layer is now composed of a three-level hierarchical structure: the mesh, micropillars and nanoparticles.</p>

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 Facile Fabrication of a Hierarchical Superhydrophobic Coating with Aluminate Coupling Agent Modified Kaolin

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Hui Li ◽  
Mengnan Qu ◽  
Zhe Sun ◽  
Jinmei He ◽  
Anning Zhou
Keyword(s):  
Surface Modification ◽  
Coupling Agent ◽  
Cost Effective ◽  
Surface Coatings ◽  
Water Repellent ◽  
Superhydrophobic Coating ◽  
Sliding Angle ◽  
Water Contact ◽  
Facile Fabrication ◽  
Large Water

A superhydrophobic coating was fabricated from the dispersion of unmodified kaolin particles and aluminate coupling agent in anhydrous ethanol. Through surface modification, water contact angle of the coating prepared by modified kaolin particles increased dramatically from 0° to 152°, and the sliding angle decreased from 90° to 3°. Scanning electron microscopy was used to examine the surface morphology. A structure composed of micro-nano hierarchical component, combined with the surface modification by aluminate coupling agent which reduced the surface energy greatly, was found to be responsible for the superhydrophobicity. The method adopted is relatively simple, facile, and cost-effective and can potentially be applied to large water-repellent surface coatings.

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