Fluorine-Free Durable Superhydrophobic Surfaces Fabricated via a Simple Spraying Method

2021 ◽  
Vol 1041 ◽  
pp. 69-73
Author(s):  
Zhi Yong Xu ◽  
Yan Yan Wang ◽  
Xing Jie Tang ◽  
Chang Si Peng

Superhydrophobic self-cleaning surfaces are based on the surface micro/nanomorphologies and special chemical regents with low surface free energy. Such surface structures are highly susceptible to mechanical wear. Moreover, the use of fluorinated compounds is harmful to both human health and environment. Herein, a simple method based on spin coating and spraying is proposed to fabricate durable fluorine-free superhydrophobic surfaces. A glass substrate was coated with a layer of water-based paint via a simple spinning process. Due to the adhesive layer, modified SiO2 nanoparticles were strongly bonded to the glass substrate. After the coating was completely cured, the surfaces realized a water contact angle of 165.1° and maintained their water repellency after 50 abrasion cycles with sandpaper and 50 times of stripping test. No chemical reagents harmful for the environment were used.

2012 ◽  
Vol 706-709 ◽  
pp. 2874-2879 ◽  
Author(s):  
R. Jafari ◽  
Masoud Farzaneh

Superhydrophobic surfaces were prepared using a very simple and low-cost method by spray coating. A high static water contact angle of about 154° was obtained by deposition of stearic acid on an aluminium alloy. However, this coating demonstrated a high contact angle hysteresis (~ 30º). On the other hand, superhydrophobic surfaces with a static contact angle of about 162º and 158º, and a low contact angle hysteresis of about 3º and 5º were respectively obtained by incorporating nanoparticles of SiO2and CaCO3in stearic acid. The excellent resulting hydrophobicity is attributed to the synergistic effects of micro/nanoroughness and low surface energy. A study of the wettability of these surfaces at temperatures ranging from 20 to-10 °C showed that the superhydrophobic surface becomes rather hydrophobic at supercooled temperatures.


2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Pran Krisna Saha ◽  
Rony Mia ◽  
Yang Zhou ◽  
Taosif Ahmed

AbstractHighly hydrophobic surfaces exhibit a remarkable feature in the repellency of oil and water. However, the relatively complex preparation process, high costs, and harmful compounds have largely limited their applications. This research aim is to fabricate hydrophobic nonwoven fabrics with low-cost and nontoxic materials. Despite various wettable materials, nonwoven cotton fabric material bearing hydrophobic surfaces has been received significant attention. This is mainly owing to its easy handling, high flexibility, environment friendly, low cost, biodegradability, high efficiency, and easily scalable fabrication. In this study, a simple chemical modification method using hexadecyltrimethoxysilane (HDTMS) with ethanol which is a better method in comparison with other methods since it is an inexpensive, simple method, and offers an easy adjustment of chemical composition required for a surface to show hydrophobic behaviors. The wetting behavior of cotton samples was investigated by water contact angle measurement. The best result comes from 2 ml HDTMS with 40 ml ethanol at 60 °C. The result shows that the treated cotton fabrics exhibited excellent chemical stability and outstanding non-wettability with the WCA of 126 ± 2°. It also shows that standard oil and water repellency, which offers an opportunity to accelerate the large-scale production of hydrophobic textile materials for new industrial applications. Graphic abstract


2010 ◽  
Vol 114 (50) ◽  
pp. 22277-22283 ◽  
Author(s):  
Sunho Jeong ◽  
Hae Chun Song ◽  
Won Woo Lee ◽  
Youngmin Choi ◽  
Sun Sook Lee ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1245
Author(s):  
Bárbara R. Gomes ◽  
Rui Araújo ◽  
Tatiana Sousa ◽  
Rita B. Figueira

The use of advanced sensing devices for concrete and reinforced concrete structures (RCS) is considered a rational approach for the assessment of repair options and scheduling of inspection and maintenance strategies. The immediate benefits are cost reduction and a reliable prevention of unpredictable events. The use of optical fiber sensors (OFS) for such purposes has increased considerably in the last few years due to their intrinsic advantages. In most of the OFS, the chemical transducer consists of immobilized chemical reagents placed in the sensing region of the optical sensor by direct deposition or by encapsulation in a polymeric matrix. The choice of the support matrix impacts directly on the performance of the OFS. In the last two decades, the development of OFS functionalized with organic–inorganic hybrid (OIH) sol–gel membranes have been reported. Sol–gel route is considered a simple method that offers several advantages when compared to traditional synthesis processes, allowing to obtain versatile materials with unique chemical and physical properties, and is particularly valuable in the design of OIH materials. This review will provide an update of the current state-of-the-art of the OFS based on OIH sol-gel materials for concrete and RCS since 2016 until mid-2021. The main achievements in the synthesis of OIH membranes for deposition on OFS will be discussed. The challenges and future directions in this field will also be considered, as well as the main limitations of OFS for RCS monitoring.


2018 ◽  
Vol 6 (8) ◽  
pp. 9958-9965 ◽  
Author(s):  
Yizhou Shen ◽  
Jie Tao ◽  
Zhong Chen ◽  
Chunling Zhu ◽  
Guanyu Wang ◽  
...  

2021 ◽  
Vol 1047 ◽  
pp. 97-102
Author(s):  
Nattanicha Khamsao ◽  
Kornkamon Waengwan ◽  
Sunisorn Konchai ◽  
Poonnapat Patthong ◽  
Bpantamars Phadungchob ◽  
...  

Seedling bags are low cost and light weight containers used by farmers to germinate and sprout seeds into seedlings before transplanting into the ground. However, cutting and removing seedling bags before the transplantation can damage the plant roots and cause losses in their productivity. In addition, plastics used in conventional seedling bags contribute to more plastic waste during this process. This study offers a solution to these problems with alternative biodegradable materials; i.e. modified papers made from an invasive alien aquatic plant species—water hyacinth—and enhanced with Chitosan solution coating. Papers were made from water hyacinth and dipped or sprayed with Chitosan solution in acetic acid at concentrations of 1% wt., 1.5% wt., and 2% wt. The dipping method showed better water barrier properties than the spraying method in every concentration, with 2% wt. concentration having the best barrier properties. The 2% wt. concentration of Chitosan coating by dipping method changed the water contact angle of the water hyacinth paper from a hydrophilic to a hydrophobic surface. This enhancement in water resistance was confirmed by water absorption time, which reached over 1.5 hours—3 times longer than the spraying method.


2019 ◽  
Vol 813 ◽  
pp. 37-42
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Edoardo Proverbio

Three different methods were used to obtain nature-inspired superhydrophobic surfaces on aluminum alloys: short-term treatment with boiling water, HF/HCl and HNO3/HCl concentrated solution etching. Afterwards a thin octadecylsilane film was deposited on all pre-treated surfaces. The surface morphology analysis showed that each method allow to obtain a specific dual nano/micro-structure. The corresponding water contact angles ranged from 160° to nearly 180°. The adhesion force between the water droplets and superhydrophobic surfaces were evaluated. The specimen etched with HF/HCl acid mixture solution showed the lowest adhesion. However, the boiling water treatment sample was characterized by the highest adhesion. Furthermore, the relationship between hydrophobic behavior and surface morphology was discussed compressively. In addition, the electrochemical measurements show that the different superhydrophobic surfaces have an excellent anti-corrosion performance evidencing promising results suitable to obtain large-scale nature-inspired superhydrophobic surfaces for several industrial applications.


Buildings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 59
Author(s):  
Barbara Francke ◽  
Artur Piekarczuk

This paper analyses the mechanism of the loss of functional properties of water-impermeable products used under ceramic tiles bonded with adhesives. Recorded damages were caused by selected ageing factors and were measured by the loss of adhesion of individual layers of the set. The analyzed phenomenon is found mainly on terraces and balconies located in a mid-European transitional climate, i.e., exposed to temperatures passing through 0 °C for three seasons a year. The tests reflected the action of three main functional factors, i.e., temperatures, water and freeze/thaw cycles. Tested waterproof coatings were grouped into three types, i.e., dispersion, cementitious and reaction resin-based products. Research kits consisted of liquid-applied water-impermeable products laid on a concrete substrate, adhesives and tiles. Comparing the effects of the action of the above-mentioned ageing factors revealed that water has the greatest impact on the reduction of the tensile adhesion strength of such sets. The adhesion of waterproof coatings to the concrete substrate showed higher values than the adhesion between the waterproof coating and the tile adhesive layers, regardless of the coating material. Both for samples not exposed to ageing factors, and for those exposed to such impacts, failure usually occurred in the adhesive layer or between the tile adhesive and the waterproof coating, without damaging the waterproof layer. The loss of adhesion of finishing layers to the substrate was not accompanied by a loss of tightness of the waterproof coating. The impact of negative water ageing was particularly destructive on the adhesion of cement-based tile adhesives to waterproof coatings made of polymer with a water dispersion of absorbability above 7% (V/V). There was no correlation among the results of adhesion of the finishing layers to the waterproofing layer after the action of the three ageing factors, i.e., water contact, elevated temperature and freeze/thaw cycles.


Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 398 ◽  
Author(s):  
Chongwei Du ◽  
Xiaoyan He ◽  
Feng Tian ◽  
Xiuqin Bai ◽  
Chengqing Yuan

Corrosion seriously limits the long-term application of Q235 carbon steel. Herein, a simple fabrication method was used to fabricate superhydrophobic surfaces on Q235 carbon steel for anticorrosion application. The combination of structure and the grafted low-surface-energy material contributed to the formation of superhydrophobic steel surfaces, which exhibited a water contact angle of 161.6° and a contact angle hysteresis of 0.8°. Meanwhile, the as-prepared superhydrophobic surface showed repellent toward different solutions with pH ranging from 1 to 14, presenting excellent chemical stability. Moreover, the acid corrosive liquid (HCl solution with pH of 1) maintained sphere-like shape on the as-prepared superhydrophobic surface at room temperature, indicating superior corrosion resistance. This work provides a simple method to fabricate superhydrophobic steel surfaces with chemical stability and corrosion resistance.


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