Durable Superhydrophobic Fabrics Research Articles

Facile UV-Induced Surface Covalent Modification to Fabricate Durable Superhydrophobic Fabric for Efficient Oil-Water Separation.

In this work, a durable superhydrophobic fabric was fabricated by using a facile UV-induced surface covalent modification strategy. 2-isocyanatoethylmethacrylate (IEM) containing isocyanate groups can react with the pre-treated hydroxylated fabric, producing IEM molecules covalently grafted onto the fabric's surface, and the double bonds of IEM and dodecafluoroheptyl methacrylate (DFMA) underwent a photo-initiated coupling reaction under UV light radiation, resulting in the DFMA molecules further grafting onto the fabric's surface. The Fourier transform infrared, X-ray photoelectron spectroscopy and scanning electron microscopy results revealed that both IEM and DFMA were covalently grafted onto the fabric's surface. The formed rough structure and grafted low-surface-energy substance contributed to the excellent superhydrophobicity (water contact angle of ~162°) of the resultant modified fabric. Notably, such a superhydrophobic fabric can be used for efficient oil-water separation, for example a high separation efficiency of over 98%. More importantly, the modified fabric exhibited excellent durable superhydrophobicity in harsh conditions such as immersion in organic solvents for 72 h, an acidic or alkali solution (pH = 1-12) for 48 h, undergoing laundry washing for 3 h, exposure to extreme temperatures (from -196° to 120°), as well as damage such as 100 cycles of tape-peeling and a 100-cycle abrasion test; the water contact angle only slightly decreased from ~162° to 155°. This was attributed to the IEM and DFMA molecules grated onto the fabric through stable covalent interactions, which could be accomplished using the facile strategy, where the alcoholysis of isocyanate and the grafting of DFMA via click coupling chemistry were integrated into one-step. Therefore, this work provides a facile one-step surface modification strategy for preparing durable superhydrophobic fabric, which is promising for efficient oil-water separation.

Preparation of self-healing superhydrophobic cotton fabric based on silica aerogel for self-cleaning and oil/water separation

Self-healing superhydrophobic coatings with excellent self-cleaning ability have received a lot of attention. A self-healing superhydrophobic cotton fabric was obtained by coating SiO2 aerogel and polydimethylsiloxane (PDMS) on a cotton fabric via the spraying process. Sol-gel reaction and ambient pressure drying (APD) were used to prepare hydrophobic SiO2 aerogel utilizing methyl trimethoxy silane (MTMS) as a precursor and water as a solvent in the presence of surfactant. Spraying a mixture of SiO2 aerogel and polydimethylsiloxane onto cotton fabric created the self-healing superhydrophobic cotton fabric. The surface morphology and chemical composition of superhydrophobic cotton fabrics were characterized respectively. The results showed that the treated cotton fabrics exhibited the superhydrophobic property with water contact angle (WCA) and water shedding angle (WSA) 161.1° ± 0.9° and 4° ± 0.5°, respectively, due to the simultaneous introduction of typical three-dimensional network porous structure caused by SiO2 aerogel and low surface tension PDMS layer on cotton fabrics. The treated cotton fabrics had not only excellent self-cleaning and anti-fouling properties, but also self-healing properties. The treated cotton fabrics showed excellent friction durability and laundering durability attributed to stable and firm PDMS adhesive layer. After 20 laundering cycles, 600 friction cycles or 8 cycles of etching-self-healing, the treated cotton fabrics were still superhydrophobic. The treated cotton fabric manifested desirable oil-water separation performance with a separation efficiency of 96.0%. These durable superhydrophobic fabrics with self-cleaning and liquid repellency may find various potential applications and display promising prospects.

Facile fabrication of durable superhydrophobic fabrics by silicon polyurethane membrane for oil/water separation

Nowadays, oil contamination has become a major reason for water pollution, and presents a global environmental challenge. Although many efforts have been devoted to the fabrication of oil/water separation materials, their practical applications are still hindered by their weak durability, poor chemical tolerance, environmental resistance, and potential negative impact on health and the environment. To overcome these drawbacks, this work offers a facile method to fabricate the eco-friendly and durable oil/water separation membrane fabrics by alkaline hydrolysis and silicon polyurethane coating. The X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy results demonstrate that silicon polyurethane membrane could be coated onto the surface of hydrolyzed polyester fabric and form a micro-/nano-scaled hierarchical structure. Based on this, the modified fabric could have a stable superhydrophobic property with a water contact angle higher than 150°, even after repeated washing and mechanical abrasion 800 times, as well as chemical corrosion. Moreover, the modified fabrics show excellent oil/water separation efficiency of up to 99% for various types of oil–water mixture. Therefore, this durable, eco-friendly and cost-efficient superhydrophobic fabric has great potential in large-scale oil/water separation.

Superhydrophobic PDMS-pCA@CNWF Composite with UV-Resistant and Self-Cleaning Properties for Oil/Water Separation.

Oil separation is crucial for avoiding environmental pollution originating from industrial wastewater and oil spillage; therefore, it is essential to develop techniques for oil separation. Herein, a new membrane with superhydrophilicity was synthesized by a facile, green, and low-cost method. First, cellulose non-woven fabric (CNWF) was modified by poly (catechin) (pCA), which has good antioxidant and antibacterial activities, to make it unaffected by ultraviolet light and to improve the stability of the structure. Then, hydrolyzed polydimethylsiloxane (PDMS) was coated on the pCA@CNWF surface via chemical bonding to make the composite hydrophobic. This durable superhydrophobic fabric can be used to separate various oil/water mixtures by gravity-driven forces with high separation efficiency (over 98.9%). Additionally, the PDMS-pCA@CNWF possesses the advantages of flexibility, high efficiency, and an outstanding self-cleaning performance, and demonstrates significant potential for applications in various environments, even under various harsh conditions, which make it very promising for the treatment of oil pollution in practical applications.

One-Step Covalent Surface Modification to Achieve Oil-Water Separation Performance of a Non-Fluorinated Durable Superhydrophobic Fabric.

In this work, a durable superhydrophobic fabric was fabricated by a facile covalent surface modification strategy, in which the anchoring of 10-undecenoyl chloride (UC) onto the fabric through the esterification reaction and covalent grafting of n-dodecyl-thiol (DT) via thiol-ene click chemistry were integrated into one step. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) measurement results demonstrated that UC and DT were covalently grafted onto the fabric surface. The formed gully-like rough structure by the grafted UC and DT on the fabric surface together with the inherent microfiber structure, combined with the grafted low-surface-energy materials of UC and DT, gave the resultant modified DT–UC@fabric superhydrophobic performance. The superhydrophobic DT–UC@fabric was used for separation of oil–water mixtures; it exhibited high separation efficiency of more than 98%. In addition, it presented excellent durability against mechanical damage; even after 100 cyclic tape-peeling and abrasion tests, the DT–UC@fabric could preserve superhydrophobic performance, which was ascribed to the formed covalent interactions between the fabric surface and the grafted UC and DT. Therefore, this work provided a facile, efficient strategy for fabricating superhydrophobic composites with excellent durability, which exhibited a promising prospect in the application of self-cleaning and oil–water separation.

Durable superhydrophobic cotton fabrics prepared by surface-initiated electrochemically mediated ATRP of polyhedral vinylsilsesquioxane and subsequent fluorination via thiol-Michael addition reaction

Fluorinated polyhedral oligomeric silsesquioxane (F-POSS) is one of the most popular candidates at present for superhydrophobic coating. Because of its ultralow surface energy, F-POSS has usually been dissolved with expensive fluoro-solvents, and the melting temperature of F-POSS is not high (122–140 °C), which will cause its loss during use. So trying to polymerize/crosslink F-POSS molecules and/or directly graft F-POSS to substrate is important. In this work, we report the SI-eATRP grafting of methacryl POSS (MA-POSS) on cotton and the subsequent amine catalyzed thiol-methacrylate Michael addition reaction of poly(MA-POSS) with 1H, 1H, 2H, 2H-perfluorododecyl-1-thiol (PFDT) for the fabrication of a durable poly(MA-POSS)-PFDT coating. The cotton fabric coated with poly(MA-POSS) was nearly superhydrophobic after 4 h of SI-eATRP process under potentiostatic condition of −0.40 V. Although the water contact angle (WCA) was ~148°, water droplets tended to adhere to the cotton fabric surface even when the fabric was turned upside down. After fluorination, WCA was increased to ~160°, and water drops could slide off when the fabric was slightly tilted. The sliding angle (SA) was ~10°. The as-prepared poly(MA-POSS)-PFDT coating was durable against repeated washing and physical abrasion. After 30 accelerated washing cycles (equals to 150 home laundering cycles), the coated fabric still showed superhydrophobicity. After 800 abrasion cycles over sandpaper, the WCA was still as high as 149°. In addition, the coated fabric had self-healing ability and could restore its superhydrophobicity after plasma etching through heat treatment. After 10 cycles of plasma etching and heat-induced healing process, the WCA of the coated fabric kept at ~154°. Such a durable superhydrophobic fabric coating may find applications in the development of functional clothing for a variety of purposes.

A robust and antibacterial superhydrophobic cotton fabric with sunlight-driven self-cleaning performance for oil/water separation

In this work, a durable and sunlight-driven self-cleaning superhydrophobic cotton fabric was developed as a multifunctional oil/water separation material. First of all, Ag/AgCl was successfully deposited on the polydopamine modified cotton fabric surface by electrostatic adsorption, then the Ag/AgCl loaded fabric was coated by the polydimethylsiloxane (PDMS) via simple dip-coating method. The as-prepared cotton fabric (PDMS-Ag/AgCl@CF) presented the superhydrophobic property with water contact angle about 155°. Meanwhile, the prepared PDMS-Ag/AgCl@CF exhibited great tolerance and resistance to broad pH and various organic solvents, and it can also withstand 50 cycles of abrasion or 60 min of ultrasound treatment without an apparent decrease of superhydrophobicity, indicating its outstanding mechanical durability. As expected, this durable superhydrophobic fabric can availably separate various oil/water mixtures by gravity-driven force with high separation efficiency (over 97.8%), and it possessed good reusability. Additionally, the PDMS-Ag/AgCl@CF exhibited an outstanding self-cleaning performance under sunlight irradiation, due to visible light photocatalytic performance of Ag/AgCl. Finally, the resultant cotton fabric displayed good antibacterial activity. Therefore, in consideration of its prominent comprehensive performances, it is expected that the PDMS-Ag/AgCl@CF can be used as a promising material for oily water remediation.

Design and fabrication of polydopamine based superhydrophobic fabrics for efficient oil–water separation

In this work, we prepare a PDMS-SiO2-PDA@fabric with high water contact angle (WCA = 155°). Combining dopamine self-polymerization and a sol-gel method, SiO2 is in situ grown on a PDA-modified fabric surface to synergistically construct micro-nano rough structures. Finally, a superhydrophobic fabric is successfully obtained after coating the fabric with a layer of PDMS. The prepared fabric can maintain superhydrophobicity after immersion in various solvents (pH = 1, 3, 5, 7, 9, 11, 13, DMF, ethanol, THF, n-hexane) for 24 h and strong ultraviolet irradiation for 60 min. Thanks to the highly reactive PDA clusters, the stronger interfacial bond between the fabric and SiO2 enables it to withstand 180 min of washing and 159.22 N tensile stress, showing strong adhesion strength. In addition, the modified fabric has excellent self-cleaning properties and is resistant to contamination such as milk, coffee and tea. More importantly, the prepared fabric can selectively repel water and adsorb oil, achieving above 90% oil-water separation efficiency even after 8 cycles.

Solvent-free fabrication of tough self-crosslinkable short-fluorinated copolymer nanocoatings for ultradurable superhydrophobic fabrics

• Tough short-fluorinated nanocoatings were fabricated by solvent-free iCVD. • Isocyanate chemistry induced self-crosslinking and fixated surface fluorinated chains. • Self-crosslinking enabled excellent dynamic water repellency and mechanical strength. • Conformal nanocoating imparted fabrics ultradurable superhydrophobicity. As long-perfluorinated side chain polymers are phasing out due to healthy and environmental concerns, short-fluorinated polymers are garnering increasing attention as a substitute for superhydrophobic coatings. Challenges, however, are to be addressed due to the poor dynamic water repellency and unsatisfactory durability of short-fluorinated polymer coatings. This work reports the fabrication of self-crosslinkable poly(perfluorohexylethyl acrylate- co -isocyanato ethyl methacrylate) nanocoating with good dynamic water repellency and high mechanical strength using a solvent-free initiated chemical vapor deposition (iCVD) method. The employment of highly reactive isocyanate groups in the coating not only facilitated covalent binding with functional groups on the substrate surface, but also enabled self-crosslinking reactions in the presence of water vapor. Crosslinking immobilized the fluorinated chains on the surface, thus alleviating the contact angle hysteresis. The crosslinked network also significantly improved the mechanical strength of the coating. Without affecting fabric morphology, the coating enabled superhydrophobicity of different fabrics with water sliding angle as low as 3˚. Such superhydrophobicity was well maintained after various harsh durability tests, including sandpaper abrasion for up to 20,000 cm, ultrasonication and boiling for more than 12 h, etc. The achieved durability was attributed to the enhanced adhesion strength and excellent mechanical property of the coating. This work thus paves a novel way towards eco-friendly fabrication of durable superhydrophobic fabrics.

Facile Generation of Durable Superhydrophobic Fabrics toward Oil/Water Separation via Thiol-Ene Click Chemistry

In this work, the superhydrophobic fabric was fabricated by surface modification with mercaptopropyltriethoxysilane (MPTES) to incorporate thiol groups, and subsequent thiol-ene click chemistry wit...

A fluorine-free method for fabricating multifunctional durable superhydrophobic fabrics

In this study, fly ash (FA), which is a waste product of common flue gas, was used to effectively fabricate multifunctional superhydrophobic surfaces. FA was first coated with a TiO2 shell layer to form a core (FA)-shell (TiO2) structure via charge adsorption. FA-TiO2 was then grafted with polydimethylsiloxane (PDMS) molecules to form FA-TiO2-PDMS particles, which exhibited superhydrophobicity. The PDMS molecules were grafted firmly on the TiO2 shell through covalent bonds, therefore endowing the particles a series of durable properties. The superhydrophobic FA-TiO2-PDMS particles mixed with PDMS could form homogenous coating solution, which was coated onto fabrics to obtain superhydrophobic surfaces. The resulting superhydrophobic fabric exhibited the “Lotus-effect” and excellent self-cleaning ability. It also showed excellent photocatalysis ability that could repeatedly photodegrade various oils and dyes. Moreover, the coated fabric showed durable and stable superhydrophobicity, which could withstand repeated abrasion treatments, recycled peeled tests using an adhesive tape, long-duration boiling-water immersion, and recycled solvent immersion. In addition, the surface exhibited strong self-healed superhydrophobicity after a simple heat treatment even after being repeatedly treated by plasma or immersed into a strong alkali/acid solution for 8 h. The superhydrophobic fabrics also achieved self-quenched fire-retardance and could efficiently separate various oil-water mixtures.

Fabrication of stable fluorine-free superhydrophobic fabrics for anti-adhesion and self-cleaning properties

This study is aimed at the fabrication of superhydrophobic fluorine-free films on cotton fabrics through incorporating a rough sub-structure followed by chemical modification. Stable titania hydrosols were prepared via sol-gel using 0.44 mol/L titanium tetraisopropoxide in acidic media followed by chemical modification of the sol using vinyltrimethoxysilane (VTMS) for surface energy reduction and spraying over the surface. Upon drying at 60 °C, covalent attachment of vinyl modified TiO2 particles to hydrophilic surface was occurred. Water contact angle increased from 0° on pure fabric up to 134.1° with sliding angles >90°. Further enhancement in water contact angles up to ∼170° and reduction of sliding angle to <10° was achieved by introduction of polydimethylsiloxane (PDMS). Hydrodynamic particle size of TiO2 sol was determined using dynamic light scattering (DLS). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Attenuated total reflectance-Fourier Transform Infra-Red (ATR-FTIR) analyses were conducted to verify the morphology and rough structure, elemental analysis and surface chemical modification of treated surfaces, respectively. Furthermore, the superhydrophobic coating was applied on a commercial sponge for oil-water separation. According to the results, self-cleaning, anti-adhesion, chemical resistant and durable super-hydrophobic fabric was prepared through spraying of low-cost environmentally friendly materials.

Magnet-responsive, superhydrophobic fabrics from waterborne, fluoride-free coatings.

In this study, durable superhydrophobic fabrics with magnet responsive properties were prepared by a two-step coating technique using polydopamine (PDA), Fe3O4 nanoparticles, and hexadecyltrimethoxysilane as coating materials. The coated fabrics exhibit fast magnetic responsivity and a water contact angle of 156°. The coating is durable enough to withstand at least 50 cycles of home laundering and 500 cycles of Martindale abrasions without losing its superhydrophobicity and magnetic properties. The PDA pre-coating plays a significant role in improving the adhesion of hydrophobic Fe3O4 nanoparticles on fabric surface. The coated fabric is highly oleophilic (oil contact angle = 0°). When used for absorbing oil, the coated fabric floats naturally on the surface of oily water, and it can be moved to approach oil drops under magnetic actuation. The fabric is reusable for at least 10 cycles. This may offer an environmentally friendly way to prepare “smart” oil-recovery materials.

Robust and durable superhydrophobic fabrics fabricated via simple Cu nanoparticles deposition route and its application in oil/water separation

The exploitation of separation materials with high selectivity for oil pollutants is of great importance due to severe environmental damage from oil spillages and industrial discharge of oils. A facile in situ growth process for creating superhydrophobic-superoleophilic fabrics for oil-water separation is developed. This proposed method is based mainly on the deposition Cu nanoparticles and subsequent hydrophobic modification. Compared with the hydrophilicity of original fabric, the water contact angle of the modified fabric rises to 154.5°, suggesting its superhydrophobicity. The as-prepared fabrics also exhibit wonderful oil-water selectivity, excellent recyclability, and high separation efficiency (>94.5%). Especially, via pumping the fabric rolled into a multilayered tube, various types of oils on water surface can be continuously separated in situ without any water uptake. Furthermore, the superhydrophobic fabrics show excellent superhydrophobic stability, and can resist different chemicals, such as salty, acidic, and alkaline solutions, oils, and hot water. After the abrasion of 400cycles, the broken fabric still possesses highly hydrophobicity with water contact angle of 145°. Therefore, due to simple fabrication steps, low cost, and scalable process, the as-prepared fabrics can be applied in the separation of oils and other organic solvents from water.

Argon Plasma Treatment of Fluorine‐Free Silane Coatings: A Facile, Environment‐Friendly Method to Prepare Durable, Superhydrophobic Fabrics

A novel method to prepare durable superhydrophobic fabrics through pre‐applying an alkyl silane (alkyl chain longer than C15) onto fabric substrate and by subsequent vacuum plasma treatment in argon is reported. The treated fabrics show a contact angle of 154.2° with low contact angle hysteresis (sliding angle 4.5°). The coatings are durable and can withstand 150 cycles of standard laundries. The argon plasma treatment is found to significantly enhance SiOSi bonding among the silane molecules, leading to a highly crosslinked silica network. The silane coating also shows high optical transparency. Apart from fabrics, other substrates such as filter paper, plastic film, glass slide, silicon wafer, and metal are treated in a similar way, and all the treated surface show durable hydrophobicity, though the contact angle is lower than that of the coated fabrics. Post‐crosslinking of silane through argon plasma treatment may offer a facile but environment‐friendly way to prepare durable superhydrophobic fabrics.

Facile process for the fabrication of durable superhydrophobic fabric with oil/water separation property

A durable superhydrophobic fabric with oil/water separation property has been successfully prepared by introducing the modified silica nanoparticles and polysiloxane. The as-prepared fabric shows liquid repellency not only to water but also to coffee, milk and tea droplets, which are normal in daily life. Furthermore, the treated fabric shows simultaneous superhydrophobicity and superoleophilicity, which could be utilized as materials to separate oil/water mixture with high efficiency. It is important to note that the obtained fabric kept stable superhydrophobicity even after it suffered severe friction damage. The surface morphologies of untreated/treated fabrics were characterized by the scanning electron microscopy. The chemical compositions were characterized by X-ray photoelectric energy spectroscopy and Fourier transform infrared spectrum. This functionalized fabric will be helpful for developing superhydrophobic and selective oil adsorption materials.