sliding angle
Recently Published Documents


TOTAL DOCUMENTS

158
(FIVE YEARS 68)

H-INDEX

12
(FIVE YEARS 4)

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 330
Author(s):  
Tien N. H. Lo ◽  
Sung Woo Hong ◽  
Ha Soo Hwang ◽  
In Park

Superhydrophobic Al surfaces with excellent durability and anti-icing properties were fabricated by coating dual-scale rough Al substrates with fluorinated polysilazane (FPSZ). Flat Al plates were etched using an acidic solution, followed by immersion in boiling water to generate hierarchical micro-nano structures on their surfaces. The FPSZ coatings were synthesized by grafting 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS-17), a fluoroalkyl silane), onto methylpolysilazane, an organopolysilazane (OPSZ) backbone. The high water contact angle (175°) and low sliding angle (1.6°) of the FPSZ-coated sample with an FAS-17 content of 17.3 wt% promoted the efficient removal of a frozen ice column with a low ice adhesion strength of 78 kPa at −20.0 °C (70% relative humidity), which was 4.3 times smaller than that of an OPSZ-coated surface. The FPSZ-coated Al surface suppressed ice nucleation, leading to a decrease in ice nucleation temperature from −19.5 to −21.9 °C and a delay in freezing time from 334 to 4914 s at −19.0 °C compared with the OPSZ-coated Al surface. Moreover, after 40 icing–melting cycles the freezing temperature of a water droplet on the FPSZ-coated Al surface remained unchanged, whereas that on the FAS-17-coated Al surface increased from −22.3 to −20.7 °C. Therefore, the durability of the polymeric FPSZ coating was superior to that of the FAS-17 monolayer coating.


Author(s):  
Junfei Huang ◽  
Jiajie Kang ◽  
Jiaxu Zhang ◽  
Jinxia Huang ◽  
Zhiguang Guo

AbstractThe harsh working environment affects the performance and usage life of Al and its alloys, thus limiting their application. In recent years, Slippery Liquid-infused Porous Surface (SLIPS) has attracted much attention due to excellent anti-corrosion, anti-fouling and anti-icing properties. This may be an effective way to improve the properties of Al and its alloys. Here, the SLIPS with petal-like structure was constructed on the Al alloy via simple hydrothermal reaction, Stearic Acid (STA) modification and lubricant injection. A variety of droplets (including oil-in-water emulsions) can slide on the SLIPS at a low angle, even the Sliding Angle (SA) of the water droplet is only 3°. Furthermore, the SLIPS exhibits outstanding mechanical and chemical properties. It can maintain fine oil-locking ability under high shearing force and keep slippery stability after immersion in acid/alkaline solutions. In addition, the SLIPS possesses excellent anti-corrosion, anti-fouling and anti-icing properties, which provides a new way to promote the application of Al and its alloys. Therefore, the SLIPS is expected to be an effective way to improve the properties of Al and its alloys, as well as play a role in anti-fouling and self-cleaning in construction, shipbuilding and automotive manufacturing industries, thereby expanding the practical application of Al and its alloys.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3354
Author(s):  
Alvaro Lafraya ◽  
Cristina Prieto ◽  
Maria Pardo-Figuerez ◽  
Alberto Chiva ◽  
Jose M. Lagaron

In the current work, a super-repellent biopaper suitable for food contact applications was developed. To do this, three different kinds of biopolymers, namely polylactide (PLA), poly(ε-caprolactone) (PCL), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and hydrophobic silica microparticles (SiO2), were sequentially processed by electrohydrodynamic processing (EDHP). As a first step, the ultrathin biopolymer fibers were deposited onto a commercial food contact cellulose paper by electrospinning and, thereafter, the nanostructured silica was sequentially electrosprayed. The multilayer coated papers were annealed at different temperatures to promote adhesion between the layers and enhance the super-repellent properties. The developed coatings were characterized in terms of morphology, permeance to water vapor, adhesion, mechanical resistance, and contact and sliding angle. The resultant multilayer biopapers presented a hierarchical micro/nanostructured surface with an apparent water contact angle (WCA) higher than 155° and sliding angle (SA) lower than 10° for all the tested biopolymers used. Among the different multilayer approaches, it was observed that the paper/PHBV/SiO2 showed the best performance, in terms of water vapor permeance; resistance after the tape peeling-off test; and food super-repelling properties to water, yogurt, and custard. Overall, this study presents the successful generation of super-repellent biopapers coated with PLA, PCL, or PHBV along with hydrophobic silica microparticles and its effectiveness for easy emptying food packaging applications to reduce food waste.


2021 ◽  
Vol 11 (12) ◽  
pp. 2004-2009
Author(s):  
Ruomei Wu ◽  
Shuai Wu ◽  
Haiyun Jiang ◽  
Zigong Chang ◽  
Zhiqing Yuan ◽  
...  

Anti-corrosion of aluminum alloys with different roughness were researched in this study. To further verify the relationship between anti-corrosion and surface roughness, surface with micro structure alloy was successfully fabricated via anode oxidation on aluminum. The water contact angle of aluminum alloy surface after coating polypropylene film was 154° and sliding angle was 3°. The micro-nano structure was constructed by adding nano-SiO2. The contacts angle of surface was 165° and the sliding angle was 1.8°. The superhydrophobic samples were used to test corrosion resistance. Compared with aluminum coated with unmodified film, the corrosion potential for modified superhydrophobic aluminum alloy increased by about 0.05 V. When nano-SiO2 particles were added, the corrosion resistance for the sample was also improved.


2021 ◽  
Vol 11 (23) ◽  
pp. 11172
Author(s):  
Zhiqiang Qian ◽  
Zhong Liu ◽  
Shidong Wang ◽  
XiuShen Ye ◽  
Zhijian Wu

A simple and practical spray method is employed to prepare a PVDF/PFOTES-SiO2 superhydrophobic composite coating on the AZ31B Mg alloy substrate. The morphology, composition, and water contact angle (CA) were measured by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM) and contact angle measuring instrument. Hydrophilic nano-SiO2 is modified by PFOTES to obtain hydrophobicity. The influence of the mass of PFOTES-SiO2 to PVDF on the hydrophobic properties was studied. The wear resistance and stability of the composite coating have been investigated by immersion test, cross-cut adhesion test and friction test. Additionally, the corrosion resistance was measured by electrochemical workstation and salt spray corrosion test. The CA of PVDF/PFOTES-SiO2 coating is 161.3° and the sliding angle (SAs) is less than 2°. After 10× the sandpaper friction test, the superhydrophobic contact angle of the coating remained above 155°, and the sliding angle was less than 5°, which indicated that the prepared coating is a strong superhydrophobic coating with good wear resistance. The results of the electrochemical tests show that the superhydrophobic coating improved the anti-corrosion performance of Mg alloy, and the water contact angle is greater than 150° after 168 h salt spray corrosion test. Due to its excellent superhydrophobicity, wear resistance and anti-corrosion properties, the robust PVDF/PFOTES-SiO2 coating is considered to have great potential for future applications in the automotive and marine industries.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7161
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Salvatore Patané ◽  
Edoardo Proverbio

Superhydrophobic surfaces on 6082 aluminum alloy substrates are tailored by low-cost chemical surface treatments coupled to a fluorine-free alkyl-silane coating deposition. In particular, three different surface treatments are investigated: boiling water, HF/HCl, and HNO3/HCl etching. The results show that the micro-nano structure and the wetting behavior are greatly influenced by the applied surface texturing treatment. After silanization, all the textured surfaces exhibit a superhydrophobic behavior. The highest water contact angle (WCA, ≈180°) is obtained by HF/HCl etching. Interestingly, the water sliding angle (WSA) is affected by the anisotropic surface characteristics. Indeed, for the HF/HCl and the HNO3/HCl samples, the WSA in the longitudinal direction is lower than the transversal one, which slightly affects the self-cleaning capacity. The results point out that the superhydrophobic behavior of the aluminum alloys surface can be easily tailored by performing a two-step procedure: (i) roughening treatment and (ii) surface chemical silanization. Considering these promising results, the aim of further studies will be to improve the knowledge and optimize the process parameters in order to tailor a superhydrophobic surface with an effective performance in terms of stability and durability.


2021 ◽  
Vol 2080 (1) ◽  
pp. 012005
Author(s):  
Yee Wen Yap ◽  
Muhammad Salihin Zakaria ◽  
Razif Muhammed Nordin ◽  
Khairul Anwar Abdul Halim ◽  
Bee Ying Lim ◽  
...  

Abstract Degradation properties of recycled plastic causing it less widely used. By adding extra physical properties, its commercial value and usage can be increased. In this current work, green self-cleaning surfaces from recycled high-density polyethylene (rHDPE) were fabricated using sucrose particles. Water contact angle and sliding angle, self-cleaning properties and surface morphology were characterized. Furthermore, the surface texture was also evaluated by conducting a surface roughness test. By creating porosity onto the rHDPE matrix, the surface exhibits an excellent self-cleaning property with a water contact angle larger than 150°. Surface morphology reveals the porosity and roughness of the surface. In this fabricating process, no chemicals were used while rHDPE is selected for the purpose. Hence, the process is environmentally friendly and low cost for self-cleaning surface fabrication.


NANO ◽  
2021 ◽  
Author(s):  
Ruoyu Sun ◽  
Zhen Li ◽  
Jing Zhao ◽  
Jiliang Mo ◽  
Yajia Pan ◽  
...  

Durable superhydrophobic aluminum alloy surfaces were prepared through a facile method: combining high-speed wire electrical discharge machining and chemical modification. Three types of pulse width were selected to machine the aluminum alloy surfaces with different levels of surface roughness. The effect of immersion time in perfluorooctanoic acid on the wettability of the aluminum alloy surfaces was examined. The contact angle of the superhydrophobic aluminum alloy surfaces was [Formula: see text], and the sliding angle was [Formula: see text]. After sanding with coarse sandpaper, the aluminum alloy surfaces still exhibited superhydrophobicity with a stroke of 450[Formula: see text]cm, indicating good mechanical durability. The prepared superhydrophobic aluminum alloy surface heated for 2[Formula: see text]h within the 190–240∘C temperature range showed favorable thermal stability. In addition, the superhydrophobic aluminum alloy surface exhibited self-cleaning property. Therefore, the superhydrophobic aluminum alloy surface prepared by using the simple mass production method showed good mechanical stability, thermal stability, and self-cleaning property, as well as broad application potential.


Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1162
Author(s):  
Rajaram S. Sutar ◽  
Saravanan Nagappan ◽  
Appasaheb K. Bhosale ◽  
Kishor Kumar Sadasivuni ◽  
Kang-Hyun Park ◽  
...  

Superhydrophobic coatings have a huge impact in various applications due to their extreme water-repellent properties. The main novelty of the current research work lies in the development of cheap, stable, superhydrophobic and self-cleaning coatings with extreme water-repellency. In this work, a composite of hydrothermally synthesized alumina (Al2O3), polymethylhydrosiloxane (PMHS) and polystyrene (PS) was deposited on a glass surface by a dip-coating technique. The Al2O3 nanoparticles form a rough structure, and low-surface-energy PHMS enhances the water-repellent properties. The composite coating revealed a water contact angle (WCA) of 171 ± 2° and a sliding angle (SA) of 3°. In the chemical analysis, Al2p, Si2p, O1s, and C1s elements were detected in the XPS survey. The prepared coating showed a self-cleaning property through the rolling action of water drops. Such a type of coating could have various industrial applications in the future.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Haji-Savameri ◽  
Saeid Norouzi-Apourvari ◽  
Ahmad Irannejad ◽  
Abdolhossein Hemmati-Sarapardeh ◽  
Mahin Schaffie ◽  
...  

AbstractInner coatings have emerged as a novel technique to prevent the deposition of paraffin, wax, scale, and corrosion of pipelines during oil production and transport. Few studies addressed this technique for preventing asphaltene deposition. In this study, two superhydrophobic inner coatings, including polytetrafluoroethylene (PTFE) coating and nanosilica coating, were fabricated on metal surfaces and the asphaltene deposition on these coated surfaces was examined. A model oil solution was prepared using asphaltene and heptol and the effect of static and dynamic flow states on the amount of asphaltene deposition on uncoated electrodes, PTFE coated electrodes, and nanosilica coated electrodes were investigated. The results showed that the PTFE coating is more effective in reducing asphaltene deposition than nanosilica coating. The PTFE coating could reduce 56% of the deposition in a static state and more than 70% in a dynamic state at an asphaltene concentration of 2000 ppm. For PTFE coating in a dynamic state, the deposition rate is negligible in long times. In addition, it was found that the type of flow state affects the asphaltene deposition kinetics. The results demonstrate that, in the static state, the nth-order kinetics model, and in the dynamic state, the double exponential models are in best agreement with the experimental data.


Sign in / Sign up

Export Citation Format

Share Document