scholarly journals Sustainable, Fluorine-Free, Low Cost and Easily Processable Materials for Hydrophobic Coatings on Flexible Plastic Substrates

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2234
Author(s):  
Carmela T. Prontera ◽  
Giuliano Sico ◽  
Maria Montanino ◽  
Anna De Girolamo Del Mauro ◽  
Paolo Tassini ◽  
...  

Zinc oxide nanoparticles (ZnONPs) and stearic acid are herein used for the preparation of hydrophobic coatings with good moisture barrier property on flexible plastic substrates. Fast, high throughput, mild and easy-to-run processing techniques, like airbrushing and gravure printing, are applied for thin films deposition of these materials. The results of this study indicated that the best hydrophobic coating in terms of water contact angle (115°) is obtained through a two-steps printing deposition of a ZnONPs layer followed by a stearic acid layer. All the deposition procedures proved to be effective in terms of water vapor barrier properties, reaching values of 0.89 g/m2/day, with a 45% reduction with respect to the bare substrate. These preliminary data are very encouraging in the perspective of a low cost and green approach for the realization of functional coatings for packaging applications.

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 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.


2016 ◽  
Vol 694 ◽  
pp. 39-43 ◽  
Author(s):  
Rose Farahiyan Munawar ◽  
Afraha Baiti Arif ◽  
Wan Nur Fateehah Wan Abdullah Shani ◽  
Mohd Asyadi Azam ◽  
Mohd Edeerozey Abd Manaf ◽  
...  

Most of the electromagnetic (EM) wave absorbers are commonly made from polymer-based materials. A large number of polymers are resistant to the environmental degradation and are thus responsible for the buildup of polymeric solid waste materials. These solid wastes cause acute environmental problems and remain undegraded for quite a long time. In a view of the awareness and concern for the problems created by the polymeric solid wastes, new biodegradable cellulosic composite with low cost and nontoxic materials, have been designed and developed. However, the properties of natural fibers that tends to absorb water, thus limiting their application. In this study, precipitated calcium carbonate (PCC) was added with stearic acid (SA) in order to generate a hydrophobic coating formulation. PCC works as filler and SA acts as surface hydrophobic modification agent. Polymer latex was then added to the coating compound as the binder. The composite surface morphology was inspected using scanning electron microscope (SEM). Results show that durian peel composite sheet had successfully achieved a superhydrophobic surface with a water contact angle of 154.85° which exceed 150°.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 487
Author(s):  
Siti Khairunisah Ghazali ◽  
Nadia Adrus ◽  
Rohah A. Majid ◽  
Fathilah Ali ◽  
Jamarosliza Jamaluddin

The elimination of mercury, low energy consumption, and low heat make the ultraviolet light-emitting diode (UV-LED) system emerge as a promising alternative to conventional UV-mercury radiation coating. Hence, a series of hydrophobic coatings based on urethane acrylate oligomer and fluorinated monomer via UV-LED photopolymerisation was designed in this paper. The presence of fluorine component at 1160 cm−1, 1235 cm−1, and 1296 cm−1 was confirmed by Fourier Transform Infra-Red spectroscopy. A considerably high degree C=C conversion (96–98%) and gel fraction (95–93%) verified the application of UV-LED as a new technique in radiation coating. It is well-accepted that fluorinated monomer can change the surface wettability as the water contact angle of the coating evolved from 88.4° to 121.2°, which, in turn, reduced its surface free energy by 70.5%. Hence, the hydrophobicity of the coating was governed by the migration of the fluorine component to the coating surface as validated by scanning electron and atomic force microscopies. However, above 4 phr of fluorinated monomer, the transparency of the cured coating examined by UV-visible spectroscopy experienced approximately a 16% reduction. In summary, the utilisation of UV-LED was a great initiative to develop green aspect in photopolymerisation, particularly in coating technology.


Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4977
Author(s):  
Tomasz Ganicz ◽  
Krystyna Rózga-Wijas

The results of the application of a new hydrophobization agent based on a triethoxymethylsilane and standard starch aqueous mixture for mass-produced cellulosic materials—printing paper, paperboard, and sack paper—have been evaluated to examine whether such a mixture can be used in industrial practice. The application of this agent on laboratory sheets prepared in a repetitive recycling process was performed to investigate its influence on the formation and properties of the products, as well as the contamination of circulating water. Measurements of the water contact angle, Cobb tests, and water penetration dynamics (PDA) were performed to test the barrier properties of the resulting materials. The effects of the applied coatings and recycling process on the paper’s tensile strength, tear index, roughness, air permeance, and ISO brightness were studied. Studies have proven that this formulation imparts relatively high surface hydrophobicity to all materials tested (contact angles above 100°) and a significant improvement in barrier properties while maintaining good mechanical and optical performance. The agent also does not interfere with the pulping and re-forming processes during recycling and increases circulation water contamination to an acceptable degree. Attenuated total reflectance Fourier-transform infrared (FT-IR) spectra of the paper samples revealed the presence of a polysiloxane network on the surface.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3549
Author(s):  
Carlos Ruzafa Silvestre ◽  
María Pilar Carbonell Blasco ◽  
Saray Ricote López ◽  
Henoc Pérez Aguilar ◽  
María Ángeles Pérez Limiñana ◽  
...  

The aim of this work is to develop hydrophobic coatings on leather materials by plasma polymerisation with a low-pressure plasma system using an organosilicon compound, such as hexamethyldisiloxane (HMDSO), as chemical precursor. The hydrophobic coatings obtained by this plasma process were evaluated with different experimental techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and standardised tests including colour measurements of the samples, surface coating thickness and water contact angle (WCA) measurements. The results obtained indicated that the monomer had polymerised correctly and completely on the leather surface creating an ultra-thin layer based on polysiloxane. The surface modification produced a water repellent effect on the leather that does not alter the visual appearance and haptic properties. Therefore, the application of the plasma deposition process showed promising results that makes it a more sustainable alternative to conventional functional coatings, thus helping to reduce the use of hazardous chemicals in the finishing process of footwear manufacturing.


Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 232 ◽  
Author(s):  
Yanpeng Xue ◽  
Shuqiang Wang ◽  
Peng Bi ◽  
Guochen Zhao ◽  
Ying Jin

Although super-hydrophobic surfaces have great application prospects in industry, their preparation cost and mechanical durability have limited their practical utilization. In this work, we presented a new low-cost process preparation for super-hydrophobic Co–Ni coating on carbon steel substrate via an electrodeposition route. The deposited Co–Ni coating with cauliflower-shaped micro-nano structures exhibited high super-hydrophobic properties with water contact angles over 161° after modification with 1H,1H,2H,2H-Perfluorooctyltrichlorosilane (PFTEOS). Evaluated by the linear abrasion methods, the super-hydrophobic coating can maintain super-hydrophobicity after abrasion distance of 12 m under the applied pressure of 5 kPa, which was attributed to the high cobalt content of the Co–Ni coating. Moreover, electrochemical tests showed that the super-hydrophobic Co–Ni coatings exhibited a good anti-corrosion performance thus providing an adequate protection to the carbon steel substrates.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 151
Author(s):  
Yuyang Liu ◽  
Chang-Hwan Choi

Sand, a cheap and naturally abundant particulate material, was modified with photocatalytic and hydrophobic coatings to reduce evaporation loss and facilitate the purification of water. The first-level photocatalytic coatings (TiO2 or ZnO nanocrystals) rendered nanoscale roughness on the surface of the sand. The additional second-level hydrophobic coating of a self-assembled monolayer of octyltrimethoxysilane (OTS) made the sand particles superhydrophobic because of the nanoscale roughness imposed by the nanocrystals. The superhydrophobic sand particles, floating on the free surface of water due to their superhydrophobicity, significantly reduced the evaporation loss of water by 60%–90% in comparison to an uncovered water surface. When the outer hydrophobic coatings are weathered or disengaged, the inner photocatalytic coatings become exposed to water. Then, the sand particles act as photocatalysts to degrade the contaminants in water under solar radiation.


2021 ◽  
Vol 13 (15) ◽  
pp. 8244
Author(s):  
Francesca Cirisano ◽  
Michele Ferrari

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.


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 646
Author(s):  
Victor Gomes Lauriano Souza ◽  
Marta M. Alves ◽  
Catarina F. Santos ◽  
Isabel A. C. Ribeiro ◽  
Carolina Rodrigues ◽  
...  

This work aimed to produce bionanocomposites of chitosan incorporated with zinc oxide nanoparticles (ZnO NPs) synthesized using food industry by-products and to characterize them. Such nanoparticles are highlighted due to their low cost, antimicrobial activity, accessibility, and sustainability synthesis. Four different levels of ZnO NPs (0, 0.5, 1.0, and 2.0% w/w of chitosan) were tested, and the bionanocomposites were characterized in terms of their hydrophobicity, mechanical, optical, and barrier properties. Overall, the incorporation of ZnO NPs changed the composites from brittle to ductile, with enhanced elongation at break and reduced Young Modulus and tensile strength. Thus, ZnO NPs acted as plasticizer, turning the films more flexible, due to the presence of organic compounds on the NPs. This also favored permeability of oxygen and of water vapor, but the good barrier properties were maintained. Optical properties did not change statistically with the ZnO NPs incorporation. Thus, the characterization presented in this paper may contribute to support a decision on the choice of the material’s final application.


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