Long-term-durable anti-icing superhydrophobic composite coatings

We prepared carbon-based superhydrophobic composite coatings through a quick technique, merging multiwalled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs) to obtain hierarchical nanostructures on fiber-reinforced polymer (FRP) sheets; this was followed by supercritical fluid (SCF) processing and physical mixing (PM). The prepared SCF–MWCNT–CNF and PM–MWCNT–CNF composite coatings showed high water contact angles of 171.6 and 160°. The surface morphologies of the composite coatings revealed a lot of even nanostructures and folding at high magnifications. A high number of CNFs were added to the MWCNTs to initiate different nanoroughnesses in the composite coatings. The as-prepared superhydrophobic composite coatings showed excellent anti-icing properties, as indicated by the supercooled water droplet (-20°C) test under environmental conditions. Also, the surface of the SCF–MWCNT–CNF superhydrophobic composite coating showed excellent antifouling properties. We studied the surface wettability increasing different temperatures (30–180°C) in the SCF–MWCNT–CNF composite; this exposed the fact that the FRP sheets were thermally stable up to 100°C, and a while later, they changed from a superhydrophobic state to a superhydrophilic state at 180°C. This study revealed an economically workable method for the preparation of MWCNT–CNF composites with SCF techniques. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47059.     

Fabrication of superhydrophobic coatings based on nanoparticles and fluoropolyurethane

Hydrophobic nanosilica or nanofluoric particles were mixed with fluoropolyurethane resin to fabricate superhydrophobic coatings that have contact angles higher than 145°. These coatings were prepared from the simple mixing of nanoparticles in fluoropolymer and were cured at room temperature. Different fractions of nanosilica, nanofluoric particles, and the combination of them were used to find the best formulations of superhydrophobic coatings. Contact angle, contact angle hysteresis, sliding angle, hardness, and UV durability tests were conducted to find the effectiveness of these coatings. The results showed that only fluoropolyurethane coatings containing nanosilica or the combination of it and fluoric particles were superhydrophobic. Also, the hardness of coatings was increased by raising nanoparticle concentrations. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

One-step fabrication of wear-resistant superhydrophobic coating based on aminosilane-functionalized diatomaceous earth

Facile fabrication of superhydrophobic coatings with excellent mechanical robustness is highly desired in practical application. Herein, a convenient and effective strategy for one-step fabrication of robust volumetric superhydrophobic coating was developed containing aminosilane-functionalized cylindrical diatomaceous earth (DE) particles and a polyurethane (PU) resin. Due to the strong chemical cross-linking between the amino groups and the isocyanates, the superhydrophobic DE particles were strongly anchored to the PU resin, thus improving the wear resistance of the coating. The coating could withstand 20 m sandpaper abrasion under a constant pressure of 2.6 kPa. The wear resistance of the coating improved nearly 471% compared with the superhydrophobic DE/PU composite coating prepared by physical-blending. Moreover, the coating also demonstrated great self-cleaning performance, excellent chemical stability and underwater durability. Additionally, the as-prepared coating could be easily applied to various substrates and exhibited high rigidity (3H-4H), good adhesion (4B-5B), and great flexibility (impact resistance of 1 Kg·m).     

Fabrication of large‐scale superhydrophobic composite films with enhanced tensile properties by multinozzle conveyor belt electrospinning

Large‐scale superhydrophobic composite films with enhanced tensile properties were prepared by multinozzle conveyor belt electrospinning. First, a strategy of conveyor belt electrospinning was introduced for large‐scale fabrication since the conveyor belt can expand the electrospinning area unlimitedly. During the electrospinning (or electrospraying) process, certain kinds of fibers are combined on the conveyor belt in one electrospinning (or electrospraying) step. The superhydrophobicity of electrospun film can be achieved by the presence of PS beads and bead‐on‐string PVDF fibers, while submicron PAN fibers are responsible for the improvement of mechanical properties. The result shows that CA value of the surface comprising of PS beads and bead‐on‐string PVDF fibers could reach up to 155.0°. As the submicron PAN fibers increased, the value of CA decreased, changing from 155.0° to 140.0°, meanwhile the tensile strength of composite film was enhanced from 1.14 to 4.12 MPa correspondingly which is beneficial to putting the films into practice. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39735.     

Facile fabrication of superhydrophobic polyaniline structures and their anticorrosive properties

We report a simple approach for the preparation of superhydrophobic polyaniline (PANI) and its application for the corrosion protection coatings. First, PANI was synthesized conventionally by oxidative polymerization with APS. Subsequently, PANI with different wettability was obtained by modification with different surfactants. The surface modification of PANI with three different surfactants (sodium dodecylbenzenesulfonate, polyethylene glycol, and cetyltrimethylammonium bromide) provided excellent surface superhydrophobicity (water contact angle >150°). The structure and morphology of as‐prepared PANI were characterized with Fourier transform infrared, Energy dispersive X‐ray spectroscopy, and Scanning electron microscopy. Corrosion protection performance of PANI with different wettability was evaluated in 3.5% NaCl electrolyte using Tafel polarization curves and electrochemical impedance spectroscopy. The results indicated that various superhydrophobic PANI coatings have better anticorrosion performance as compared to the hydrophilic PANI. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44248.     

Incorporation of different proportions of polytetrafluoroethylene and graphene into polyethersulfone matrix as efficient anticorrosive coatings

To solve defects existing in polyethersulfone (PES) coatings and improve their performance, polytetrafluoroethylene (PTFE) and functionalized graphene (fG) are incorporated into PES coatings to develop a new PES-PTFE/fG coating. The incorporation vastly improves the anticorrosion properties of the coatings due to the synergistic effect of PTFE's low surface energy and fG's “labyrinth effect” and their filling effects. Moreover, results of research on the effects of different adding proportions of PTFE and fG on coatings properties show that PES-PTFE/fG₁ exhibits the lowest water absorption and still possesses high anticorrosion properties after long-term corrosion tests, suggesting that it has optimal anticorrosion properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47942.     

Facile preparation of a crosslinked hydrophilic UHMWPE membrane

Ultra high molecular weight polyethylene (UHMWPE) filters are widely used in water treatment. In the present work, a facile crosslinking technique is first applied to a UHMWPE flat membrane as a model to realize long-lasting hydrophilicity and improved water treatment efficiency. In the presence of a crosslinker, N, N′-methylene bisacrylamide (MBA), 2-hydroxyethyl methacrylate (HEMA), a hydrophilic modifier, is soaked into the surface of UHMWPE particles by blending. Then, a crosslinking reaction occurs during the initial sintering stage. Finally, sintering is completed at high temperature and pressure. The FTIR and SEM results show that HEMA is successfully crosslinked on the UHMWPE particle surface. Compared to a pristine membrane, the crosslinked UHMWPE flat membrane presents a lower water contact angle and is more rapidly penetrated by water. As a result, the crosslinked membrane can realize pressureless filtration. Another meaningful result is that the water flux recovery rate (FRR) is extremely high both for BSA and sludge filtration tests. Also a parameter K of 1 was obtained to represent the efficiency of the membrane treatment of water under pressureless conditions. These findings demonstrate that the crosslinking strategy is an effective method for realizing long-lasting hydrophilicity and is very promising for UHMWPE filters and other engineering applications.     

Effect of polyurethane sizing on carbon fibers surface and interfacial adhesion of fiber/polyamide 6 composites

Commercial epoxy sized carbon fibers (CFs) or unsized CFs have poor interfacial adhesion with polyamide 6 (PA6). Here, CFs are coated with polyurethane (PU) and their surface properties in terms of surface chemistry, contact angle, roughness, and morphology, are investigated. The results of Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy demonstrate PU sizing evidently increases the quantity of polar functional groups on the CFs surface. The surface energy of the PU sized fiber is calculated according to the Owens–Wendt method. Compared with unsized fibers, the contact angle of PU sized fibers is decreased while their total surface energy is increased, indicating superior wettability. Moreover, transverse fiber bundle tests are performed to determine the interfacial adhesion between the CFs and PA6 matrix. The transverse fiber bundle strength of unsized CF is measured to be 12.57 MPa. For PU sized CFs processed with sizing concentration of 1.2%, this value is increased to 24.35 MPa, showing an increase of more than 90%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46111.     

Facile fabrication of near-infrared light-responsive shape memory nanocomposite scaffolds with hierarchical porous structures

In this work, the near-infrared (NIR) light-responsive shape memory scaffolds with hierarchical porous structures are designed and facilely formed by freeze drying of 3D printed viscous gel-like pickering emulsions, which are stabilized by hydrophobically modified graphene oxide (g-GO) and silica nanoparticles, and contain thermo-responsive poly(d , l -lactic acid-co-trimethylene carbonate) (PLMC) in the oil phase. The prepared scaffolds display an interconnected filament structure with hierarchical pores and high porosity. The incorporation of g-GO nanoparticles into PLMC matrix prompts that the scaffold shape memory can be triggered by NIR light with fast shape recovery. Moreover, the in vitro mineralization experiment shows that the scaffolds have biological activity, and the drug release study demonstrates that the scaffolds can be used as drug carriers with efficient drug release capacity. Furthermore, cell culture assays based on mouse bone mesenchymal stem cells exhibit that the scaffolds own good cytocompatibility. Therefore, the facile preparation and remote activation of the shape memory nanocomposite scaffolds with hierarchical porous structure and multifunctionality represents a highly attractive candidate as minimally invasive implantation scaffolds for bone tissue engineering applications.     

Biomineralized polypropylene/CaCO3 composite nonwoven meshes for oil/water separation

Polypropylene/calcium carbonate (CaCO₃) composite nonwoven meshes were prepared on the basic principle of biomineralization by using a facile alternate soaking process (ASP) within 20 min. Negatively charged poly(acrylic acid) brushes, which can induce CaCO₃ nucleation, were first tethered onto the fiber surface of polypropylene nonwoven meshes via UV‐induced graft polymerization. ASP procedure was followed to mineralize CaCO₃ particles on the fiber surface and to form the composite nonwoven meshes. Fourier transform infrared spectroscopy/attenuated total reflectance, field emission scanning electron microscope, equipped X‐ray spectroscope, and X‐ray diffraction were used to characterize the prepared composite meshes. The mineral cover density increased with the ASP cycles, and it progressively increased for the relative content of calcite in the crystalline part of the mineral layer as well. Contact angle measurements indicate that the as‐prepared composite nonwoven meshes were endowed with superhydrophilicity and underwater superoleophobicity, thus they showed prominent application prospects in wastewater treatment and oil/water separation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39897.     

One-step fabrication of superhydrophobic sponge with magnetic controllable and flame-retardancy for oil removing and collecting

Water pollution arising from oil spillage and chemical leakage has emerged as a critical problem imposing threat to the human and animal health. Effective removal of oils and chemical from water has become a global challenge. Recently, superhydrophobic/superoleophilic magnetic controllable (SHPB-SOPI-MC) porous materials have attracted more attention in the field of oil-removing because of the high selectivity, large absorption capacity, easy collection, and ideal recyclability. Moreover, in order to keep safety, the fire proofing performance should be taken into consideration. Therefore, fabricating SHPB-SOPI-MC porous materials with flame-retardancy through a low cost and simple strategy is necessary but also challenging. In this work, an ultrasound-assisted dip-coating method was applied to fabricate polydimethylsiloxane-vermiculite-Fe₃O₄ (PDMS-VMT-Fe₃O₄) coating onto discarded polyurethane (d-PU) sponge, which exhibited superhydrophobic, superoleophilic, magnetic controllable, and flame-resistant properties. The PDMS-VMT-Fe₃O₄@d-PU sponge owned excellent mechanical durability, chemical stability, and long-term storage stability. Importantly, the PDMS-VMT-Fe₃O₄@d-PU sponge instantly adsorbed oil floating on water under magnetic field driving. Furthermore, PDMS-VMT-Fe₃O₄@d-PU sponge absorbed various oils and chemical with ideal selectivity, absorption capacity (up to 40 times of its own weight), speed, and recyclability (exceeding 100 cycles). These findings suggested that PDMS-VMT-Fe₃O₄@d-PU sponge was a promising oil-removing material for practical application of oil spills cleanup.     

In situ preparation of polyaniline within neutral,anionic, and cationic superporous cryogel networks as conductive,semi‐interpenetrating polymer network cryogel composite systems

Polyaniline [p(An)], one of the most known conducting polymers, was prepared within superporus nonionic polyacrylamide [p(AAm)], anionic poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid sodium salt) [p(AMPS)], and cationic poly(3‐acrylamidopropyltrimethyl ammonium chloride) [p(APTMACl)] cryogels. After they were synthesized, washed, and dried, the neutral p(AAm), anionic p(AMPS), and cationic p(APTMACl) cryogels were soaked in an ammonium persulfate/aniline solution (1:1.25 ratio) in 1 M hydrochloric acid for the in situ oxidative polymerization of p(An) with the cryogel matrices as templates or reactors. The prepared p(AAm)/p(An), p(AMPS)/p(An), and p(APTMACl)/p(An) semi‐interpenetrating polymer network (semi‐IPN) conductive cryogel composites were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and conductivity analysis. The SEM images revealed that the superporus cryogel networks were almost completely filled with p(An) conductive polymers (CPs). Among the cryogel–CP semi‐IPNs, we found that p(AAm)/p(An) semi‐IPN conductive cryogel composites provided the highest conductivity values of 1.4 × 10^?2 ± 4 × 10^?4 S/cm; this was a 6.4 × 10⁶ fold increase in the conductivity from the values of 2.2 × 10^?9 ± 1 × 10^?10 for p(AAm) cryogels. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44137.     

High oil absorbable superhydrophobic melamine sponges and evaluation in oil spill clean-ups

Facing the environmental crisis to leakage of oil spills and chemicals, multifunctional absorbent with high oil absorption and selectivity urgently need to solve this matter. In our work, a high oil sorbent was designed and favorably fabricated by two simple immersions using melamine sponge as pristine and a series of oils were used to evaluate the oil absorption performances of the absorbent. Two immersions include adhesion of dopamine and grafting of the long chain hydrophobic agent. The prepared material is superhydrophobic with water contact angle is 165.9° ± 2.17 and high oil absorption to chloroform is 174 times by own weight, other oils are close to or over 100 times, but to water is only 0.5 times. The reusability reveals that the average recovery can keep more than 95% after 20 cycles. These advantages make it really potential to use in oil spill clean.     

Water vapor permeability and self-cleaning properties of solvent-free polyurethane improved by hollow nano-TiO2 spheres

In the synthetic leather industry, solvent-free polyurethane film (SFPU) was poor in water vapor permeability (WVP) and washability. In this study, we introduced the hollow nano-TiO₂ spheres (HNTSs) with high photocatalytic performance and permeability performance as well as large surface area into the SFPU film to endued its superior water vapor permeability property, self-cleaning performance and water resistance. First of all, HNTSs were prepared via the controllable chemical route using HF for internal corrosion of solid nano-TiO₂ spheres, and then introduced into hydroxyl prepolymer to prepare solvent-free polyurethane/HNTSs composite film. The results of SEM, FT-IR and UV analyses indicated HNTSs were successfully dispersed evenly into SFPU. Application experiment results showed that the addition of HNTSs with hollow structure had an important effect on the WVP, photocatalytic performance, mechanical property, the water vapor transmission rate, self-cleaning performance as well as tensile strength were increased by 111.98%, more than 100%, and 36.368%, respectively.     

3D-Printed thermoplastic polyurethane/graphene composite with porous segregated structure: Toward ultralow percolation threshold and great strain sensitivity

Low-percolation threshold and large deformation capacity are two critical attributes of the strain sensor, which determine its sensitivity and stability respectively. However, endowing these two attributes to the strain sensor simultaneously is still a great challenge in this field. In this work, the strain sensor with the three-dimensional porous segregated structure constructed by graphene wrapped thermoplastic polyurethane (TPU) particles was fabricated successfully through the selective laser sintering technology. Results demonstrated that the percolation threshold of the composite is only 0.2 wt% and the strain gage factor can reach as high as 668.3, which represents the excellent sensitivity of the strain sensor. Furthermore, after 10 circles of stretching at the 15% strain, resistance-strain behavior of the strain sensor shows great repeatable, which represents the remarkable stability. Therefore, the highly sensible and stable strain sensor was fabricated successfully, which will provide the guidance for the manufacture of the high-performance strain sensor.     

Facile preparation of superhydrophobic polyester surfaces with fluoropolymer/SiO2 nanocomposites based on vinyl nanosilica hydrosols

A facile method to prepare superhydrophobic fluoropolymer/SiO₂ nanocomposites coating on polyester (PET) fabrics was presented. The vinyl nanosilica (V? SiO₂) hydrosols were prepared via one‐step water‐based sol‐gel reaction with vinyl trimethoxy silane as the precursors in the presence of the base catalyst and composite surfactant. Based on the V? SiO₂ hydrosol, a fluorinated acrylic polymer/silica (FAP/SiO₂) nanocomposite was prepared by emulsion polymerization. The FAP/SiO₂ nanocomposites were coated onto the polyester fabrics by one‐step process to achieve superhydrophobic surfaces. The results showed that silica nanoparticles were successfully incorporated into the FAP/SiO₂ nanocomposites, and a specific surface topography and a low surface free energy were simultaneously introduced onto PET fibers. The prepared PET fabric showed excellent superhydrophobicity with a water contact angle of 151.5° for a 5 μL water droplet and a water shedding angle of 12° for a 15 μL. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40340.     

Assessment of high performance SAPO-34/S-PEEK composite coatings for adsorption heat pumps

In this work, a new composite adsorbent coating on aluminum support, based on SAPO34 zeolite filler embedded into sulfonate polyether ether ketone matrix is investigated for adsorption heat pumps (AHP) applications. Composite zeolite/polymer mixtures, with 80–95 wt% content of SAPO-34 zeolite filler have been prepared and coated on aluminum substrates. The as prepared coatings showed a pull-off adhesion strength up to 2.0 MPa, significantly higher than conventional values of composite zeolite coatings reported in the literature. Scanning electron microscopy analysis demonstrated that the coating has a homogeneous morphology with zeolite filler well interconnected in the composite coating structure. Water adsorption isobars were carried out at equilibrium in the temperature range 30–120°C. The best adsorption performances for AHPs applications were observed for the PZ-95 batch, where a maximum water uptake of ∼29.0 wt% was reached, highlighting that the polymer matrix presence does not alter the zeolite adsorption capability (31.3 wt%).     

The influence of size and healing content on the performance of extrinsic self-healing coatings

Among the several approaches for the protection of metallic structures from corrosion, covering with a polymeric coating has attracted more attention due to their convenient application, cost-effective price, and the relatively benign environmental impact. However, the polymeric coatings are sensitive to mechanical/thermal shocks and aggressive environments, leading to damages in the coatings that affect their barrier performance. Self-healing polymeric coatings have introduced remarkable development by extending the service life and reducing maintenance costs, leading to a significant boost in the reliability and durability of the conventional polymeric coatings. Among the different strategies to develop self-polymeric coatings, encapsulating healing agent within micro/nanocapsules, micro/nanofibers, and microvascular systems and incorporating them within the conventional coatings have been widely acknowledged as the most applicable approach. However, several factors, such as the effect of the healing system's size and content, have a significant influence on healing performance. Therefore, this review aims to reveal the effects of healing system size and healing content on the self-healing performance in polymeric coatings through the analysis of recently published articles.     

Facile fabrication of diatomite-based sponge with high biocompatibility and rapid hemostasis

Excessive bleeding causes a large part of deaths in wars and accidents. It is necessary to prepare a hemostatic material with excellent performance and low cost through a facile strategy. Herein, the diatomite is modified with (3-Aminopropyl) triethoxysilane (APTES) to endow the aminated diatomite (ADia) with positive charge and interface compatibility with chitosan (CS) and sodium alginate (SA). Then, the facile fabrication of CS/SA/ADia sponge is successfully obtained by cross-linking with calcium ions. Compared to CS/SA sponge, the introduction of ADia further enhances the mechanical properties and hemostatic performance of CS/SA-based sponges. The composite sponges with 30 wt% ADia are demonstrated to possess high biocompatibility, compressive strength, water adsorption, and rapid hemostatic capability both in vitro and in vivo. The hemostatic performance is interpreted by activation of coagulation factors and platelets in intrinsic pathway, promotion of blood cell adhesion and formation of fibrin network. Our work provides an effective strategy to develop rapid hemostatic materials with low cost and high efficiency.