Superamphiphobic Materials Research Articles

Aerogel structure used for fabricating superamphiphobic materials with self-cleaning property

Since the lotus effect was reported by Barthlott and Neinhuis in 1997, superhydrophobic and superoleophobic materials have received much attention due to special rough morphology and great potential applications in self-cleaning, anti-fouling, corrosion-resistance, and other fields. However, the conventional preparation process of superamphiphobic materials is complicated, including pre- and post-treatments which are used to achieve micro-nano hierarchical structures and low surface energy. In this study, we used methyltrimethoxysilane (MTMS) and 1,1,2,2- tetrahydroperfluorodecyltrimethoxysilane (FAS-17) as precursors and successfully prepared superamphiphobic FAS-17/MTMS composite aerogel via facile sol-gel method. Three-dimensional networks and long fluorocarbon chains formed micro-nano hierarchical structures. As-prepared aerogels had water contact angle (WCA) of 153.68°, oil contact angle (OCA) of 156.28°, water sliding angle (WSA) of 3.32° and oil sliding angle (OSA) of 4.57°, suggesting excellent superamphiphobic performance. Besides external superamphiphobicity, the cross section of sample also exhibited great liquid-repellency with WCA of 160.43° and OCA of 153.43°. Moreover, although cracked into powders with particle size of 0.1 mm, aerogel sample still retained its liquid-repellency with WCA of 122.85° and OCA of 128.01°, respectively. After thermal treatment under 200 ℃ for 2 h, the aerogel sample had WCA of 152.45° and OCA of 135.67°, showing excellent thermal stability. Taking advantage of low thermal conductivity and superamphiphobic properties, superamphiphobic aerogel has potential for fabricating self-cleaning and thermal insulating materials.

Heating repairable superamphiphobic coatings for long-lasting antifouling application

Superamphiphobic materials exhibit broader applications and possess greater potential compared to their superhydrophobic counterparts. Therefore, it is crucial for superamphiphobic coatings to exhibit applications while maintaining a long service life. To address this challenge, the surface of natural clay kaolin particles was modified through the reaction of ethyl orthosilicate and 1 H, 1 H, 2 H, 2 H -perfluorodecyl triethoxysilane to form organic-inorganic cage fluorinated polyhedral oligomeric silsesquioxane (fluoroPOS) modifiers. Subsequently, antimicrobial ZnO nanoparticles were prepared in situ using hydrothermal methods. Finally, a durable superamphiphobic coating was achieved by physical blending of a polydimethylsiloxane (PDMS) solution with the superamphiphobic powder. Experimental results demonstrate that the as-prepared ZnO/kaolin@fluoroPOS/PDMS coatings are resistant to water, milk, coffee, soy sauce, tea, sunflower oil, lubricant base oils, and other everyday liquids at contact angles greater than 150 degrees, demonstrating superior superamphiphobic and self-cleaning properties. Moreover, the coatings can withstand harsh external environments such as strong acid and alkali chemical corrosion, high temperature heating, photo-radiation aging, mechanical friction and wear, and show good durability. More importantly, the low surface energy fluoroPOS can spontaneously migrate from the interior of the coating to the surface when exposed to heat, thus restoring their impaired superamphiphobic properties. The coatings also have good antimicrobial adhesion due to the incorporation of ZnO nanoparticles. In addition, coatings can be fabricated on a variety of soft and hard substrate materials, such as cotton fabrics, sponges, aluminum sheets, and wood. Therefore, the repairable and durable superamphiphobic antifouling coatings constructed in this study are expected to find applications in many areas, such as building coatings, oil and gas pipelines, fluid drag reduction, and biological anti-corrosion.

Drop impact on viscous liquid films

When a liquid drop falls on a solid substrate, the air layer between them delays the occurrence of liquid–solid contact. For impacts on smooth substrates, the air film can even prevent wetting, allowing the drop to bounce off with dynamics identical to that observed for impacts on superamphiphobic materials. In this paper, we investigate similar bouncing phenomena, occurring on viscous liquid films, that mimic atomically smooth substrates, with the goal to probe their effective repellency. We elucidate the mechanisms associated with the bouncing to non-bouncing (floating) transition using experiments, simulations, and a minimal model that predicts the main characteristics of drop impact, the contact time and the coefficient of restitution. In the case of highly viscous or very thin films, the impact dynamics is not affected by the presence of the viscous film. Within this substrate-independent limit, bouncing is suppressed once the drop viscosity exceeds a critical value, as on superamphiphobic substrates. For thicker or less viscous films, both the drop and film properties influence the rebound dynamics and conspire to inhibit bouncing above a critical film thickness. This substrate-dependent regime also admits a limit, for low-viscosity drops, in which the film properties alone determine the limits of repellency.

Superamphiphobic coatings based on graphene oxide with abrasion resistant property by a simple method

Due to the excellent physiochemical properties of graphene oxide (GO), the fabrication of superamphiphobic coatings based on GO can explore the application fields of GO. Herein, superamphiphobic GO coatings are fabricated by simple dip coating GO and organosilane polymer (GO-FAS) dispersion on the cotton fabric, with GO acting as solid lubricant originating from its low friction coefficient. Through compound with PS/PTFE and PVDF-HFP/FAS, the PVDF-HFP/FAS/GO-FAS coating exhibit enhanced anti-abrasion property and can withstand 200 cycles of sandpaper abrasion. This study provides an opportunity for the applications of graphene oxide as superamphiphobic materials.

Preparation of PFDTS-kaolin/PU superamphiphobic coatings with antibacterial, antifouling and improved durability property

Superamphiphobic materials have a higher and broader application value compared to superhydrophobic materials. Nevertheless, durability has always been an obstacle to its practical application. Herein, we report a method that utilizes 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDTS) as an esterification reaction modifier agent for kaolin, and polyurethane as adhesive binding to substrates, so as to construct inorganic/polymer composite coatings, for obtaining a durability superamphiphobic material. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterization reveal that kaolin is successfully grafted by PFDTS. Thermogravimetry and differential scanning calorimetry tests exhibit that the material can withstand temperatures up to 400 °C. The self-cleaning test demonstrates that the as-prepared coating is repulsive to a variety of liquids such as water, milk, mud, olive oil, and n-hexadecane, which has a surface tension as low as 27.5 mN/m. It still maintains superamphiphobicity after the material is polished by sandpaper and the retention rate is above 96 % when the friction distance is about 4500 cm. After soaking in strong acid and strong base, it shows superior acid resistance and favorable alkali resistance. After aging durability irradiation for 300 min, it still retains superamphiphobicity. In addition, the biological contamination resistance tests indicate that it has a certain adhesion resistance to gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli. Therefore, it is a promising kind of durable anti-fouling material for underground oil pipelines and construction.

Sepiolite-based superamphiphobic coating with excellent robustness, chemical stability and self-cleaning performance

In recent years, the fabrication of multifunctional superamphiphobic materials has received increasingly attention. In the present study, a kind of superamphiphobic coating with low-cost, good robustness, chemical stability and self-cleaning property was prepared through spraying epoxy resin (EP) and natural sepiolite (SEP) modified by fluorinated polysiloxane (FPOS). The proposed coating (SEP@FPOS/EP) exhibited excellent superamphiphobicity to water, ordinary liquid and oil, even sunflower oil with a surface energy as low as 27 mN m−1. Moreover, due to the addition of EP, the coating still maintained good superamphiphobicity even after being impacted by 100 g sand. This suggested that it had excellent mechanical stability. Besides, the SEP@FPOS/EP coating showed good repellent to aqueous solution with pH values from 1 to 13, salty solution as well as water droplets at different temperatures. Moreover, the SEP@FPOS/EP coating could keep excellent superamphiphobicity under UV light or after being placed in an environment of −10 °C. More importantly, the SEP@FPOS/EP coating had low adhesion to water, oil and dirty, indicating it owned superior self-cleaning property. All these outstanding performances and the facile fabrication method confirmed that SEP@FPOS/EP superamphiphobic coating could be used in various fields and large-scale production.

Two-Step Approach for Fabrication of Durable Superamphiphobic Fabrics for Self-Cleaning, Antifouling, and On-Demand Oil/Water Separation

Superamphiphobic materials have attracted lots of attention due to its wide applications in many fields. However, the preparation of most superamphiphobic materials was time-consuming and complicat...

Novel coating system on poly(ethylene terephthalate) fabrics with mechanically durable liquid-repellence: Application as flexible materials with striking loading capacity

Construction of the superamphiphobic materials and their application is of particular interest both in academia and industrial circles for years. Herein, a novel coating system for fabricating superamphiphobic poly(ethylene terephthalate) (PET) fabrics was reported based on both aminopropyltriethoxysilane (APTES) and environment-friendly perfluorooctyltriethoxysilane (FAS) co-modified SiO2 nano-particles, 3-Hydroxytyramine hydrochloride (Dopamine), amino-terminated silicone oils and etched PET fabrics via the one-step Schiff-base reaction and Michael addition reaction. The prepared fabrics displayed superamphiphobic properties, with contact angles of various liquids approaching 150°. In addition, the mechanical durability superamphiphobic fabrics were obtained, which were able to withstand 500 cycles of abrasion test, 20 cycles of sand abrasion test or 20 times standard washing. Furthermore, various liquids, including water and high viscous liquids, can easily slide off the surface of the obtained fabrics in a short time at a small angle. The prepared fabric can not only float on water or oil, but also hold up 25.7 times its own body weight things floated on water or 9 times on sesame oil without sinking. This novel and effective coating system can have more potential applications in the development of soft micro-devices working on liquid surfaces, especially on highly viscous liquid surfaces or under the environment with harsh conditions.

Fabrication of durable superamphiphobic materials on various substrates with wear-resistance and self-cleaning performance from kaolin

In recent years, the fabrication of superamphiphobic materials has become a hot topic, especially the material with wear abrasion resistance. In this study, the anti-abrasion and self-cleaning superamphiphobic materials were successfully fabricated by employing kaolin particles and silanes via a simple drop coating method. The as-prepared materials show excellent superamphiphobicity to water, ordinary liquids and kinds of oils, even the hexadecane with surface tension as low as 27.5 mN·m−1. With respect to the mechanical durability, the fabricated material can still maintain its superamphiphobicity even after 180 cm abrasion using sandpaper. The excellent investigation results concerning to chemical durability, self-cleaning property, repellent to corrosion liquids, resistant to ultraviolet radiation and water dripping prove that the fabricated material is robust and multifunctional, which will increase more opportunities for practical applications. Apart from these general applications, the as-fabricated materials can be easily applied to various substrates. These multifunctional properties and the facile preparation method are expected to provide unique benefits for a wide range of applications in resistance mechanical abrasion and large-scale production.

Multifunctional superamphiphobic SiO2 coating for crude oil transportation

Superamphiphobic materials are helping with urgent issues due to increasing industrial oil transportation, as well as common oil pollution, which has triggered large interest owing to their high application value and practicability. However, they are difficult to be fabricated because of the peculiarly shaped surface structures and the substrate-dependent property, and hence, their practical applications has been immensely limited. Herein, we prepare a hierarchical superamphiphobic FOTS-SiO2 powder via a reduction reaction and self-assembly functionalization. Owing to the substrate-independent character and excellent super-repellency of the powder, it can be applied to various substrates to fabricate superamphiphobic coatings. The prepared coatings have a wide range of liquids repellency to water, oils, and even to low-surface-tension liquids like 60 wt% ethanol-water solution (25.48 mN·m−1) and n-decane (23.8 mN·m−1). What’s more, the coatings also own great water/oil-proofing ability, excellent chemical stability, antifouling and self-cleaning property. Apart from these general performances, we find that the coating has terrific anti-crude-oil-adhesion property, which endows it a new application—crude oil transportation with high efficiency (2.9 ± 0.09 mL/s). All of these advantages will endow the superamphiphobic FOTS-SiO2 particles with broad application prospects, including foodservice industry, petroleum exploitation, crude oil transportation industry, and so on.

Facile Selective and Diverse Fabrication of Superhydrophobic, Superoleophobic-Superhydrophilic and Superamphiphobic Materials from Kaolin.

As the starting material, kaolin is selectively and diversely fabricated to the superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic materials, respectively. The wettability of the kaolin surface can be selectively controlled and regulated to different superwetting states by choosing the corresponding modification reagent. The procedure is facile to operate, and no special technique or equipment is required. In addition, the procedure is cost-effective and time-saving and the obtained super-repellent properties are very stable. The X-ray photoelectron spectroscopy analysis demonstrates different changes of kaolin particles surfaces which are responsible for the different super-repellency. The scanning electron microscopy displays geometric micro- and nanometer structures of the obtained three kinds of super-repellent materials. The results show that kaolin has good applications in many kinds of superwetting materials. The method demonstrated in this paper provides a new strategy for regulating and controlling the wettability of solid surfaces selectively, diversely, and comprehensively.

A new approach to understand the Cassie state of liquids on superamphiphobic materials.

A hierarchical structure is a prerequisite for a liquid super-repellent surface due to its capability to catch large numbers of fine air-pockets. In the present work, a series of hierarchical nanocomposites with anti-wettability were fabricated by in situ deposition of spherical SiO2 nanoparticles on Te@C nanofibers. N2 adsorption-desorption isotherms were used for the first time to characterize the air-pockets and relate them to the wettability of the nanocomposites. The results indicate that superamphiphobicity is a contribution of a delicate synergistic effect between a micro-scale structure and a nano-scale structure. Significant dominance of either of them led to reduced superamphiphobicity. The superamphiphobic "beads on a string" materials should meet the following features: higher SBET that ensures enough air-pockets (SBET value of the superamphiphobic sample is much higher than that of the superhydrophobic one); and the most important, a "continuous and balanced" distribution of micro and macro air-pockets derived from hierarchical structures.

Ag Nanoparticle-Loaded Hierarchical Superamphiphobic Surface on an Al Substrate with Enhanced Anticorrosion and Antibacterial Properties

This paper presents a facile method for preparing Ag nanoparticle (NP)-loaded superamphiphobic surfaces on an Al substrate with efficient anticorrosion and antibacterial properties. A hierarchical steplike microstructure with nanopores is fabricated on an Al surface through facile chemical etching and anodization; subsequent fluorination confers superhydrophobic and superoleophobic properties to this surface. Ag NPs are loaded on the surface nanopores and stabilized by a self-assembled aminopropyltriethoxysilane monolayer through amino-group bonding to prevent aggregation and loss of Ag NPs. Compared with Ag NP-loaded pristine Al substrates, the Ag NP-coated superamphiphobic surface can effectively prevent corrosion of the Al substrate and bacterial absorption, as confirmed by electrochemical impedance spectroscopy, Tafel plot measurement, and bactericidal tests. This study provides novel insights into functional superamphiphobic materials with anticorrosion and antibacterial properties.

Preparation of superamphiphobic polymer-based coatings via spray- and dip-coating strategies

Abstract The widespread usage of superamphiphobic surfaces could dramatically improve our lives. For example, we may lead a life with little need for laundry, no need to clean electronic products, cars or buildings. In addition, virtually any liquid could be spilled onto a surface without causing undesirable wetness or stains. Considering the performance and technological requirements of various industrial sectors, the use of polymer-based coatings is an outstanding approach to fabricate durable and multifunctional superamphiphobic surfaces at a low cost. In this review, the processes used to prepare superamphiphobic polymer-based coatings by spray- and dip-coating methods will be highlighted, and the compositions and properties of these materials will also be discussed. It is hoped that this review will provide inspiration and help with the design of applicable superamphiphobic materials, and will demonstrate the diverse range of applications of superamphiphobic materials.

Fabrication of superamphiphobic-textured surfaces with reversibly switchable wettability

To realize switchable wettability for water and oils, we firstly design a facile approach to achieve superamphiphobic-textured surfaces that display the apparent contact angles greater than 150° and the sliding angles smaller than 10° for various liquids, such as water and hexadecane. Then, plasma treatment and surface fluorination were performed on the superamphiphobic surface. The tunability of the chemical composition, along with hierarchical rough surface structure, gave rise to reversibly switchable wettability between superamphiphobicity and superamphiphilicity. The wettability of the textured surface was demonstrated by visible experimental results and measurements. The reason of switchable wettability can be confirmed by X-ray photoelectron spectroscopy analysis. These results give a useful attempt in simultaneously and reversibly switching wettability for water and oils, which may have potential application in functional superamphiphobic materials.

Sprayed superamphiphobic coatings on copper substrate with enhanced corrosive resistance

The oil fouling and limited corrosion resistance problem severely hindered the use of copper, one of important engineering materials, in practical applications. Herein to address this problem, we fabricated a superamphiphobic coating on copper substrate by spray coating. The resulting superamphiphobic surface supports the Cassie–Baxter regime with apparent contact angles of more than 150° and low contact angle hysteresis to water and organic liquids with low surface tension. The resulting superamphiphobic surface also possesses enhanced corrosion resistance, allowing it to exhibit a more positive corrosion potential and a more negative corrosion current density than pristine copper substrate. Moreover, the surface wettability can be tuning by varying the surface composition of the coating. This study represents a key addition to functional superamphiphobic materials.

A Superamphiphobic Macroporous Silicone Monolith with Marshmallow‐like Flexibility

A monolithic material has marshmallow-like flexibility and superamphiphobic properties on any cutting surface. The two-step synthesis consists of a simple sol–gel process to obtain vinyl-modified superhydrophobic monolithic gels and grafting of perfluoroalkyl groups onto the pore surface to decrease surface energy. These superamphiphobic materials float on water and even on organic liquids with low polarity, such as alkanes.