Facile Fabrication of Super-Hydrophobic Surfaces by Spray PTFE

2015 ◽  
Vol 645-646 ◽  
pp. 115-119
Author(s):  
Yang Wang ◽  
Hai Feng Zhang ◽  
Xiao Wei Liu

We have developed a combination of electro –deposition and spraying methods to prepare water-repellent tin oxide/ polytetrafluoroethylene(SnO2/PTFE) coating. The coating has a high water contact angle. The resulting porous and lowest surface energy hydrophobic groups (-CF3) has a water contact angle of 165° and a sliding angle of 7°, showing super-hydrophobic property. The coating with good adhesion on substrates and the long-term stability can be fabricated on various metal substrates.

2018 ◽  
Vol 89 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
Rongrong Yu ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
Jianhua Ran ◽  
...  

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.


Soft Matter ◽  
2021 ◽  
Author(s):  
Jixi Zhang ◽  
Ligui Zhang ◽  
Xiao Gong

In this work, we prepare a PDMS-SiO2-PDA@fabric with high water contact angle (WCA=155o). Combining dopamine self-polymerization and sol-gel method, SiO2 is in situ grown on a PDA-modified fabric surface to...


2009 ◽  
Vol 620-622 ◽  
pp. 741-744 ◽  
Author(s):  
Rui Weng ◽  
Chong Rui Wang ◽  
Lian Meng Zhang ◽  
Shui Ping Wang

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.


2017 ◽  
Vol 7 ◽  
pp. 184798041770279 ◽  
Author(s):  
Baojiang Liu ◽  
Taizhou Tian ◽  
Jinlong Yao ◽  
Changgen Huang ◽  
Wenjun Tang ◽  
...  

A robust superhydrophobic organosilica sol-gel-based coating on a cotton fabric substrate was successfully fabricated via a cost-effective one-step method. The coating was prepared by modification of silica nanoparticles with siloxane having long alkyl chain that allow to reduce surface energy. The coating on cotton fabric exhibited water contact angle of 151.6°. The surface morphology was evaluated by scanning electron microscopy, and surface chemical composition was measured with X-ray photoelectron spectroscopy. Results showed the enhanced superhydrophobicity that was attributed to the synergistic effect of roughness created by the random distribution of silica nanoparticles and the low surface energy imparted of long-chain alkane siloxane. In addition, the coating also showed excellent durability against washing treatments. Even after washed for 30 times, the specimen still had a water contact angle of 130°, indicating an obvious water-repellent property. With this outstanding property, the robust superhydrophobic coating exhibited a prospective application in textiles and plastics.


RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29275-29283 ◽  
Author(s):  
Aoyun Zhuang ◽  
Ruijin Liao ◽  
Sebastian C. Dixon ◽  
Yao Lu ◽  
Sanjayan Sathasivam ◽  
...  

Hierarchical micro/nano-structured transparent superhydrophobic polytetrafluoroethylene films with water contact angle 168°, water sliding angle <1° and visible transmittance >90% were prepared on glass via aerosol-assisted chemical vapor deposition.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2474 ◽  
Author(s):  
Hao Wu ◽  
Hao Li ◽  
Ahmad Umar ◽  
Yao Wang ◽  
Guofu Zhou

Fluoropolymers play an essential role in electrowetting (EW) systems. However, no fluoropolymer possesses the desirable properties of both hydrophobicity and dielectric strength. In this study, for the first time, we report the integration of two representative fluoropolymers—namely, Teflon AF (AF 1600X) and Cytop (Cytop 809A)—into one bifunctionalized dielectric nanolayer. Within this nanolayer, both the superior hydrophobicity of Teflon AF and the excellent dielectric strength of Cytop were able to be retained. Each composed of a 0.5 μm Cytop bottom layer and a 0.06 μm Teflon AF top layer, the fabricated composite nanolayers showed a high withstand voltage of ~70 V (a dielectric strength of 125 V/μm) and a high water contact angle of ~120°. The electrowetting and dielectric properties of various film thicknesses were also systemically investigated. Through detailed study, it was observed that the thicker Teflon AF top layers produced no obvious enhancement of the Cytop/Teflon AF stack.


2008 ◽  
Vol 1132 ◽  
Author(s):  
Mehdi Shafiei ◽  
Ahmet T. Alpas

ABSTRACTA new method to fabricate superhydrophobic hard films is described. Surface texture of lotus leaf was replicated on an acetate film, on which a nanocrystalline (NC) Ni coating with a grain size of 30 ± 4 nm and a hardness of 4.42 GPa was electrodeposited. The surface texture consisted of conical protuberances with a height of 10.0 ± 2.0 0m and a tip radius of 2.5 ± 0.5 0m. An additional electrodeposition for 120 s and 300 s was used to locally modify the surface structure by depositing ‘Ni crowns' on the protuberances that increased their height to 14.0 ± 2.0 0m and their tip radius to 6.0 ± 0.5 0m. The modified structures were then treated with a perfluoropolyether (PFPE) solution, which provided a high water contact angle of 156°, i.e., comparable to the naturally superhydrophobic lotus leaf. The increased hydrophobicity as a result of surface structure and chemistry modifications was evident compared to a smooth NC Ni sample, which had a contact angle of 64°.


2008 ◽  
Vol 3 (4) ◽  
pp. 155892500800300 ◽  
Author(s):  
Karthik Ramaratnam ◽  
Swaminatha K. Iyer ◽  
Mark K. Kinnan ◽  
George Chumanov ◽  
Phillip J. Brown ◽  
...  

It is well established that the water wettability of materials is governed by both the chemical composition and the geometrical microstructure of the surface.1 Traditional textile wet processing treatments do indeed rely fundamentally upon complete wetting out of a textile structure to achieve satisfactory performance.2 However, the complexities introduced through the heterogeneous nature of the fiber surfaces, the nature of the fiber composition and the actual construction of the textile material create difficulties in attempting to predict the exact wettability of a particular textile material. For many applications the ability of a finished fabric to exhibit water repellency (in other words low wettability) is essential2 and potential applications of highly water repellent textile materials include rainwear, upholstery, protective clothing, sportswear, and automobile interior fabrics. Recent research indicates that such applications may benefit from a new generation of water repellent materials that make use of the “lotus effect” to provide ultrahydrophobic textile materials.3,4 Ultrahydrophobic surfaces are typically termed as the surfaces that show a water contact angle greater than 150°C with very low contact angle hysteresis.4 In the case of textile materials, the level of hydrophobicity is often determined by measuring the static water contact angle only, since it is difficult to measure the contact angle hysteresis on a textile fabric because of the high levels of roughness inherent in textile structures.


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