Superhydrophobic Nanocomposite Films Research Articles

Functionalized superhydrophobic MWCNT/PEI nanocomposite film with anti-icing and photo-/electrothermal deicing properties

Ice accumulation often threatens the safety of human life and property. How to effectively solve the problem of solid surface icing has been the research work of many researchers. However, how to prepare superhydrophobic and anti-icing film with multi-strategy collaborative deicing is still facing great challenges. In this paper, a design strategy of photothermal and electrothermal superhydrophobic nanocomposite film based on polyetherimide (PEI) was proposed. Multi-walled carbon nanotubes (MWCNT) were dispersed in PEI matrix by solution blending method, and a lotus leaf like rectangular micropillar array was constructed on the surface of the film by laser etching technology. Then, the surface was fluorinated to further reduce the surface energy. Finally, a kind of MWCNT/PEI nanocomposite film with passive anti-icing and active deicing with photothermal and electrothermal collaboration was successfully prepared. The freezing time of droplets on MWCNT/PEI nanocomposite film is about 6.7 times longer than that of pure PEI film. This film exhibits excellent superhydrophobicity (CA = 156.6°), while also having excellent photothermal and electrothermal conversion properties. In addition, we also conducted various tests on MWCNT/PEI nanocomposite film to verify its reliability in the actual application environment. The MWCNT/PEI nanocomposite film with the function of anti-icing and photothermal and electrothermal active deicing is expected to solve the problem of solid surface icing in daily life, and also provides a new idea for the development of a new generation of anti-icing/deicing film.

Fabrication of Self-Healable, Robust, and Superhydrophobic Nanocomposite Films

Despite the recent advances in nature-inspired superhydrophobic surfaces with multifunctional properties such as self-healing, self-cleaning, antibacterial material, anti-biofouling, and oil-water separation in various industrial applications, there have been very few reports of robust superhydrophobic surfaces fabricated via a low-cost method. Herein, we report a rationally designed, self-healable, robust, and superhydrophobic nanocomposite film, fabricated by a one-step reaction process from a multi-component solution. These superhydrophobic nanocomposite films can be readily fabricated over a large area with high throughput via simple spray coating of the component solution. As the spray-coating materials, we used functionalized hydrophobic silica nanoparticles (hydrophobic-SiO2 NPs) to achieve hierarchical textured structures, and low surface energy. Then, thermal crosslinkers and long hydrocarbon silanes were added to improve the stability and hydrophobicity of the fabricated nanocomposite films. Because of the synergetic effect of the hydrophobic NPs and crosslinked polymeric compounds, the spray-coated superhydrophobic nanocomposite films exhibited excellent superhydrophobicity (static water contact angles > 150°), high transparency (>80%), high stability, and self-healing abilities. Tests confirmed the rationally designed, solution-based spray coating method provides a simple route to construct transparent, robust, and self-healing superhydrophobic surfaces, with high throughput and large area, which can be utilized in various industrial applications, including conventional products and advanced non-wetting surfaces.

Fabrication of Self-Healable, Robust Superhydrophobic Surfaces Using UV-Crosslinked Nanocomposite Films.

Studies on fabricating robust superhydrophobic surfaces by a low-cost method have been rare, despite the recent demand for nature-inspired superhydrophobic surfaces including self-healing ability in various industrial applications. Herein, we propose a fabrication method for self-healable, robust superhydrophobic nanocomposite films by facile solution-processed spray coating and UV curing. The components of the coating solution include functionalized hydrophobic silica nanoparticles for producing high roughness hierarchical textured structures with low surface energy, and UV-crosslinkable v-POSS and bi-thiol hydrocarbon molecules to improve the film stability. As a result of the synergetic effect of the hydrophobic nanoparticles and UV-crosslinked polymeric compounds, the spray-coated and UV-cured nanocomposite films possess excellent superhydrophobicity (water contact angles > 150º) and high stability, in addition to self-healing abilities.

Facile fabrication of self-healing superhydrophobic nanocomposite films enabled by near-infrared light

A novel robust self-healing superhydrophobic F-SiO2/Fe3O4/EP(epoxy)/PCL nanocomposite film was fabricated through a facile two-step method including resin spraying and NPs perpendicular gradient deposition. Specially, the epoxy/polycaprolactone (EP/PCL) mixed resin matrix was prepared through a spraying process and the functioned silica/magnetic iron oxide (F-SiO2/Fe3O4) nanoparticles were then deposited on the resin matrix by gradient distribution under gravity and solvent evaporation. The THF/ethanol mixture solvent which acted as film microstructure-directing agent guided the F-SiO2/Fe3O4 nanoparticles gradient distribution in the nanocomposite films. The results showed that the cutting cracks on the nanocomposite film could be rapidly self-healed and the film would maintain its superhydrophobicity after irradiation by near-infrared light. The nanocomposite films, especially the F-SiO2(8.5wt%)/Fe3O4(1.0wt%)/EP/PCL nanocomposite film, showed high resistant properties on abrasion, corrosive liquids and UV irradiation. The recovery mechanism of the nanocomposite films was also investigated.

Preparation and properties of super hydrophobic films from siloxane-modified two-component waterborne polyurethane and hydrophobic nano SiO2

Nanocomposite films with super hydrophobic surface were prepared by building rough micro/nano structure on the surface of siloxane-modified two-component waterborne polyurethane (2K-WPU) with hydrophobic nano SiO2. Firstly, nano SiO2 prepared by StÖber method with tetraethoxysilane (TEOS) as precursor was modified with trimethylethoxysilane (TMES), in order to cover a layer of hydrophobic methyl groups on the surface of nano SiO2. Then, a series of nanocomposite films with different water contact angles were obtained by adding different contents of TMES modified SiO2 into the siloxane-modified 2K-WPU. The effects of the content of nano SiO2 on the morphology and hydrophobicity of film surface were investigated. The results showed that the surface structures of the nanocomposite films became rougher and the water contact angle of nanocomposite films was increased obviously with the increase of the content of hydrophobic nano SiO2. Super hydrophobic nanocomposite film with water contact angle over 150° was successfully fabricated by using polysiloxane as low surface energy material and hydrophobic nano SiO2 as micro/nano rough structure builder on the polymer surface. Moreover, incorporating nano SiO2 into the 2K-WPU matrix could increase the glass transition temperature and thermal stability of the nanocomposite films.

Superhydrophobic nanocomposite coatings with photoinitiated three-dimensional networks based on reactive graphene nanosheet-induced self-wrinkling patterned surfaces

HypothesisBionic superhydrophobicity including high contact angle, low sliding angle and nonstick property, combined with both strong pH and ultraviolet (UV) resistance, is difficult to simultaneously achieve for large-scale preparation of superhydrophobic surfaces by blending polymer with a nonreactive inorganic nanofiller. ExperimentsA series of high pH and UV-irradiation-resistant superhydrophobic nanocomposite films were prepared through UV-light-assisted chemical cross-linking among ternary components under nitrogen protection. Ethoxylated bisphenol A diacrylate, 2-(perfluorooctyl) ethyl acrylate, reactive thiol-coupled graphene nanosheets and photoinitiator were evenly mixed, followed by UV-irradiation curing. FindingsAbundant 3D networks could be formed. A robust self-wrinkling surface morphology was formed due to a UV-curing-induced inner tension in the composites, 2D morphology-induced flexibility for graphene nanosheets and fluorine-bearing component-induced phase separation at the wetted surfaces. High roughness and use of the fluorine element endows the surfaces with superhydrophobicity and oleophobicity. A favorable nonstick performance was obtained. Superhydrophobicity could be maintained despite changing the film-forming substrate, pH of soaking solutions from 1 to 12, or use of a prolonged UV-irradiation time reaching 120 h. Therefore, both superhydrophobicity/oleophobicity and strong pH/UV resistance are finely balanced. This work might open up the way for large-scale fabrication of promising superhydrophobic surfaces.

Interfacing superhydrophobic silica nanoparticle films with graphene and thermoplastic polyurethane for wear/abrasion resistance

HypothesisNanoparticle films are one of the most suitable platforms for obtaining sub-micrometer and nanometer dual-scale surface texture required for liquid repellency. The assembly of superhydrophobic nanoparticles into conformal and strongly adherent films having abrasion-induced wear resistance still poses a significant challenge. Various techniques have been developed over the years to render nanoparticle films with good liquid repellent properties and transparency. However, forming abrasion resistant superhydrophobic nanoparticle films on hard surfaces is challenging. One possibility is to partially embed or weld nanoparticles in thin thermoplastic primers applied over metals. ExperimentsHexamethyldisilazane-functionalized fumed silica nanoparticle films spray deposited on aluminum surfaces were rendered abrasion resistant by thermally welding them into thermoplastic polyurethane (TPU) primer applied a priori over aluminum. Different solvents, nanoparticle concentrations and annealing temperatures were studied to optimize nanoparticle film morphology and hydrophobicity. FindingsThermal annealing at 150 °C enhanced stability and wear resistance of nanoparticle films. A thin thermal interface layer of graphene nanoplatelets (GnPs) between the primer and the nanoparticle film significantly improved superhydrophobic wear resistance after annealing. As such, superhydrophobic nanocomposite films with the GnPs thermal interface layer displayed superior abrasion-induced wear resistance under 20 kPa compared to films having no GnPs-based thermal interface.

A facile fabrication of superhydrophobic nanocomposite coating with contact angles approaching the theoretical limit

Although there are many viable approaches to induce hydrophobicity, a superhydrophobic surface could only be fabricated by combination of surface chemistry modification and roughness enhancement. In this study, surface roughness was obtained by 12nm SiO2 nanoparticles (NPs) which were chemically modified using a self-assembled monolayer of perfluorodecyltrichlorosilane. The SiO2 NPs which were rendered hydrophobic, then successfully dispersed into a poly silicon (silsesquioxane) matrix at varying concentrations from 0.5 to 4%. The NPs dispersed polymer suspension was then spray coated on to glass and aluminum coupons in order to achieve polymer thin film nanocomposites. The results were revealed a superhydrophobic surface with a water contact angle exceeding 178° with low hysteresis and bouncing water droplet behavior. Furthermore the composite film reliability (hot-humid and ice build-up) was tested in an environmental control chamber by precisely adjusting both temperature (85°C) and relative humidity (85 RH). Taber abrasion testing was applied in order to gain insights into the abrasion resistance of nanocomposite film. Finally, ice formation was simulated at −20°C on the superhydrophobic nanocomposite film coated substrates.

A highly durable silica/polyimide superhydrophobic nanocomposite film with excellent thermal stability and abrasion-resistant performance

Superhydrophobic silica/PI nanocomposite film with comprehensive dependent high performances is easily electrospun.

Fabrication of stable, transparent and superhydrophobic nanocomposite films with polystyrene functionalized carbon nanotubes

Stable, transparent and superhydrophobic carbon nanotube (CNT) nanocomposite films were fabricated by one-step spray casting process using the polystyrene functionalized CNTs, which were prepared by “living” free-radical polymerization and analyzed by means of infrared spectroscopy and thermal gravimetric analysis. The CNT film has a high water contact angle of 160° and a sliding angle of less than 3°. The surface topography of the fabricated film was characterized by field emission scanning electron microscopy. The transparency of the CNT film was investigated by UV–vis spectroscopy. The result shows that the CNT film has light transmittance of about 78% in the visible light region.