Vanadium Pentoxide-Enwrapped Polydiphenylamine/Polyurethane Nanocomposite: High-Performance Anticorrosive Coating

Satisfactory Tensile Strength and Strain of Recyclable Polyurethane with a Trimaleimide Structure for Thermal Self-Healing and Anticorrosive Coatings

Bismaleimide (BMI) is often used as the cross-linking reagent in Diels-Alder (D-A)-type intrinsic self-healing materials (DISMs) to promote the connectivity of damaged surfaces based on reversible D-A bond formation on the molecular scale. Until now, although DISMs have exhibited great potential in the applications of various sensors, electronic skin, and artificial muscles, it is still difficult to prepare DISMs with satisfactory self-healing abilities and high tensile strengths and strains at the same time, thus largely limiting their applications in self-healing anticorrosive coatings. Herein, symmetrical trimaleimide (TMI) was successfully synthesized, and trimaleimide-structured D-A self-healing polyurethane (TMI-DA-PU) was prepared via the reversible D-A reaction (cycloaddition of furan and maleimide). As a DISM, TMI-DA-PU exhibits apparently higher self-healing efficiency (98.7%), tensile strength (25.4 MPa), and strain (1378%) compared to bismaleimide-structured D-A self-healing polyurethane (BMI-DA-PU) (self-healing efficiency, 90.2%; tensile strength, 19.3 MPa; strain, 1174%). In addition, TMI-DA-PU shows a high recycling efficiency (>95%) after 4 cycles of recycling. A series of characterizations indicate that TMI provides more monoene rings as the self-healing sites, forms denser cross-linked structures compared to BMI, and is, thus, more appropriate to be used for DISM applications. Moreover, the barrier abilities of coatings can be semi-quantitatively expressed by the impedance value at 0.01 Hz (|Z|0.01 Hz). The |Z|0.01 Hz value of the TMI-DA-PU coating is 3.93 × 109 Ω cm2 on day 0, which is significantly higher than that of the BMI-DA-PU coating (6.76 × 108 Ω cm2 on day 0), indicating that the denser rigid cross-linked structure of TMI results in the small porosity in the TMI-DA-PU coating, thus effectively improving the anticorrosion performance. The construction of DISMs with the structure of TMI demonstrates immense potential in self-healing anticorrosive coatings.

Construction of Reinforced Self-Cleaning and Efficient Photothermal PDMS@GDY@Cu Sponges toward Anticorrosion and Antibacterial Applications

Copper (Cu)-based materials are widely used in many fields from industry to life, including marine, medical apparatus and instruments, and microelectronic devices owing to their superior thermal, electrical, and mechanical properties. However, the interaction of copper with aggressive and fouling liquids under normal circumstances easily brings about severe bacterial accumulation, resulting in undesirable functionality degeneration and bacterial infections. In this contribution, we reported a novel copper-based sponge, polydimethylsiloxane (PDMS)@graphdiyne (GDY)@Cu, constructed by in situ synthesis of GDY on a commercial Cu sponge, followed by the modification of PDMS. The as-fabricated PDMS@GDY@Cu sponge not only possesses excellent self-cleaning activity against the pollution of daily drinks and dirt due to an improved static contact angle (~136°), but also display a remarkably enhanced anticorrosion performance, attributed to intimate coverage of chemically stable GDY and PDMS on the Cu sponge. Based on high photothermal effect of GDY, the PDMS@GDY@Cu sponge also displays significantly improved antibacterial activities under irradiation. In addition, due to excellent chemical stability of PDMS and GDY, self-cleaning behavior and photothermal-assisted antibacterial performance are well maintained after long-term attack of bacteria. These results demonstrate that GDY-based functional coatings hold great promises in the protection of copper devices under harsh conditions.

Engineering of Graphdiyne-Based Functional Coatings for the Protection of Arbitrary Shapes of Copper Substrates

Copper-based materials are very important for many application fields from marine industry to energy management and electronic devices. For most of these applications, the copper objects require long-term contact to a wet and salty environment, which leads to serious corrosion of copper. In this work, we report a thin graphdiyne layer directly grown on arbitrary shapes of copper objects at mild conditions, which could function as a protective coating for the copper substrates in artificial seawater with corrosion inhibition efficiency of ∼99.75%. To further improve the protective performance of the coating, the graphdiyne layer is fluorinated and followed by infusion with a fluorine-containing lubricant (i.e., perfluoropolyether). As a result, a slippery surface is obtained, which shows enhanced corrosion inhibition efficiency of ∼99.99% as well as excellent antibiofouling properties against microorganisms, such as protein and algae. Finally, the coatings are successfully applied in the protection of a commercial copper radiator from long-term attack of artificial seawater without disturbing its thermal conductivity. These results demonstrate the great potential of graphdiyne-based functional coatings for the protection of copper devices in aggressive environments.

Development of Metallo (Calcium/Magnesium) Polyurethane Nanocomposites for Anti-Corrosive Applications

Long-term corrosion protection of metals might be provided by nanocomposite coatings having synergistic qualities. In this perspective, rapeseed oil-based polyurethane (ROPU) and nanocomposites with calcium and magnesium ions were designed. The structure of these nanocomposites was established through Fourier-transform infrared spectroscopy (FT-IR). The morphological studies were carried out using scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). Their thermal characteristics were studied using thermogravimetric analysis (TGA). Electrochemical experiments were applied for the assessment of the corrosion inhibition performance of these coatings in 3.5 wt. % NaCl solution for 7 days. After completion of the test, the results revealed a very low i_corr value of 7.73 × 10^-10 A cm^-2, a low corrosion rate of 8.342 × 10^-5 mpy, impedance 1.0 × 10⁷ Ω cm², and phase angle (approx 90°). These findings demonstrated that nanocomposite coatings outperformed ordinary ROPU and other published methods in terms of anticorrosive activity. The excellent anti-corrosive characteristic of the suggested nanocomposite coatings opens up new possibilities for the creation of advanced high-performance coatings for a variety of metal industries.

Enhancement of Anticorrosive Performance of Cardanol Based Polyurethane Coatings by Incorporating Magnetic Hydroxyapatite Nanoparticles

The present investigation demonstrates renewable cardanol-based polyol for the formulation of nanocomposite polyurethane (PU) coatings. The functional and structural features of cardanol polyol and nanoparticles were studied using FT-IR and 1H NMR spectroscopic techniques. The magnetic hydroxyapatite nanoparticles (MHAPs) were dispersed 1–5% in PU formulations to develop nanocomposite anticorrosive coatings. An increase in the strength of MHAP increased the anticorrosive performance as examined by immersion and electrochemical methods. The nanocomposite PU coatings showed good coating properties, viz., gloss, pencil hardness, flexibility, cross-cut adhesion, and chemical resistance. Additionally, the coatings were also studied for surface morphology, wetting, and thermal properties by scanning electron microscope (SEM), contact angle, and thermogravimetric analysis (TGA), respectively. The hydrophobic nature of PU coatings increased by the addition of MHAP, and an optimum result (105°) was observed in 3% loading. The developed coatings revealed its hydrophobic nature with excellent anticorrosive performance.

Fabrication of metal incorporated polymer composite: An excellent antibacterial agent

US Food and Drug Administration (FDA) allowed for direct addition of castor oil for human consumption as food and most recently FDA approved castor oil as over-the-counter (OTC) for laxative drug. The present article highlights the green route phosphorylation of castor oil (COL) via condensation polymerization. Further, the incorporation of metal ions Cu (II)) and Zn (II) into the polymer matrix have been carried out at elevated temperature using catalyst p-toluene sulphonic acid (PTSA). The modification of the said material has been confirmed by FT-IR, UV-VIS, and ¹H and ³¹P-NMR spectroscopy. Further, the in vitro antibacterial activities of the metal incorporated-COL has been performed by standard methods against B. cereus (MCC2243) (gram-positive) and E. coli (MCC2412) (gram-negative) bacteria. The results revealed that the incorporation of metal ions into the polymer matrix increases the antibacterial activity largely. This may be governed by the electrostatic interaction between metal ions and microbes, also the generation of free active oxygen hinders the normal activity of bacteria. These results suggest that the synthesized material may act a potential candidate for low cost, environment friendly antibacterial agents and may find their application in clinical fields. Herein we are also proposing mechanism of antibacterial activity.

Experimental and DFT studies of porous carbon covalently functionalized by polyaniline as a corrosion inhibition barrier on nickel-based alloys in acidic media

In acidic medium, nickel alloys severely suffer from long term corrosion problems as a result of the breakdown of their passivating oxide. The present study considers polyaniline functionalized fish-scale graphitic carbon as an anticorrosion coating on the nickel alloy surface. The fish-scale porous carbon materials are characterized by XRD, ATR-FITR, UV, Raman, TGA, SS NMR, FESEM, and TEM methods. The surface of the alloy is covalently bound with a polyaniline long chain protonated polymer so that the polyaniline functionalized honeycomb fish-scale carbon structure can exchange electrons with the metal surface. The corrosion inhibition efficiency has been investigated in different acid media like sulfuric acid and hydrochloric acid by electrochemical methods. Polyaniline functionalized porous carbon showed in 1 M H₂SO₄ inhibition efficiency around 64% and in 1 M HCl inhibition efficiency was around 74%. The inhibition efficiency was higher in HCl because chloride ions were not able to penetrate the graphitic sheet. The novelty of this coating is in the fact that the polyaniline functionalized porous carbon has high conductivity and is electrochemically stable in acidic medium. It is able to donate electrons to the polarized metal surface.

Polyaniline functionalized fish scale carbon chemisorption on 111 nickel alloy surface by polyaniline polaron nitrogen free electron.

Mechanically robust hydrophobic interpenetrating polymer network-based nanocomposite of hyperbranched polyurethane and polystyrene as an effective anticorrosive coating

Facile fabrication of Si/RGO reinforced interpenetrating polymer network-based nanocomposites with inherent surface hydrophobicity and anticorrosive attributes.

Influence of carbon nanodots encapsulated polycarbazole hybrid on the corrosion inhibition performance of polyurethane nanocomposite coatings

Carbon nanodots encapsulated in a polycarbazole hybrid-dispersed polyurethane nanocomposite coating with new exciting perspectives for high-performance anticorrosive coatings are shown.