Microwave-Assisted Self-Healable Biovitrimer/rGO Framework for Anticorrosion Applications

Microwave-stimulated smart self-healable polymeric coatings with significant protective technology against corrosion have been developed in this work. Herein, a generous approach is strategized to generate linseed oil-derived epoxy composites embedded with reduced graphene oxide (rGO) as a nanofiller in the shielding network. The composite showed excellent self-healing and shape memory properties when irradiated with microwaves due to the dynamic reversible nature of the disulfide covalent bond exchange mechanism. The network also has improved thermomechanical properties and thermal stability, with a storage modulus of 20.8 GPa and a low activation energy of 79 kJ/mol, indicating a fast disulfide dynamic exchange reaction. The amine functionality in the composite contributes to excellent corrosion protection, with 99.9% protection efficiency, as validated via a Tafel plot. The composite also showed excellent hydrophobicity, with a 131° contact angle. This study provides insights into the engineering and application of smart materials as anticorrosive coatings.

Durable graphene-based alkyd nanocomposites for surface coating applications

Recently, the scientific community's main goal is the long-term sustainability. Vegetable oils are easily accessible, non-depletable, and cost-effective materials. Vegetable oils are used to prepare polymeric alkyd surfaces. Novel and exciting designs of alkyd/graphene nanocomposites have provided eco-friendly thermal stability and protective coating surfaces. This review has briefly described important graphene-based alkyd nanocomposites along with their applications as protective coatings. These alkyd composites have high hydrophobicity, corrosion resistance, and durability. Graphene-based alkyd nanocoatings have many industrial and research interests because of their exceptional thermal and chemical properties. This work introduces an advanced horizon for developing protective nanocomposite coatings. The anti-corrosion properties and coatings' longevity may be improved by combining the synergistic effects of hybrid nanofillers introduced in this work.

Sustainable smart anti-corrosion coating materials derived from vegetable oil derivatives: a review

Sustainable development is a critical concern in this fast-paced technological world. Therefore, it is essential to employ renewable resources to move towards sustainable development goals (SDGs). The polyols attained from renewable resources, including lignin, chitosan, vegetable oils, cellulose, etc. and the polymers derived from them have attracted the attention of the majority of researchers, both in academia and industry. The development of bio-based polymers from vegetable oils start emerging with different properties to generate a value-added system. This review will give an impression to readers about how coatings generated from vegetable oils can find a way towards better protective properties against corrosion either by using fillers or by using molecular structure modifications in the system, thus covering a range of vegetable oil-based self-healing polymers and their application in anti-corrosion coatings.

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.

Biomimetic surface coatings for marine antifouling: Natural antifoulants, synthetic polymers and surface microtopography

Marine biofouling is a ubiquitous problem that accompanies human marine activities and marine industries. It exerts detrimental impacts on the economy, environment, ecology, and safety. Traditionally, mainstream approaches utilize metal ions to prevent biological contamination, but this also leads to environmental pollution and damage to the ecosystem. Efficient and environmentally friendly coatings are urgently needed to prevent marine devices from biofouling. Since nature is always the best teacher for humans, it offers us delightful thoughts on the research and development of high-efficiency, broad-spectrum and eco-friendly antifouling coatings. In this work, we focus on the research frontier of marine antifouling coatings from a bionic perspective. Enlightened by three distinctive dimensions of bionics: chemical molecule bionic, physiological mechanism bionic, and physical structure bionic, the research status of three main bioinspired strategies, which are natural antifoulants, bioinspired polymeric antifouling coatings, and biomimetic surface microtopographies, respectively, are demonstrated. The antifouling mechanisms are further interpreted based on biomimetic comprehension. The main fabrication methods and antifouling performances of these coatings are presented along with their advantages and drawbacks. Finally, the challenges are summarized, and future research prospects are proposed. It is believed that biomimetic antifouling strategies will contribute to the development of nontoxic antifouling techniques with exceptional repellency and stability.

Engineering nanoscale hierarchical morphologies and geometrical shapes for microbial inactivation in aqueous solution

Here, we study the effect of hierarchical and one-dimensional (1D) metal oxide nanorods (H-NRs) such as γ-Al₂O₃, β-MnO₂, and ZnO as microbial inhibitors on the antimicrobial efficiency in aqueous solution. These microbial inhibitors are fabricated in a diverse range of nanoscale hierarchical morphologies and geometrical shapes that have effective surface exposure, and well-defined 1D orientation. For instance, γ-Al₂O₃ H-NRs with 20 nm width and ˂0.5 μm length are grown dominantly in the [400] direction. The wurtzite structures of β-MnO₂ H-NRs with 30 nm width and 0.5-1 μm length are preferentially oriented in the [100] direction. Longitudinal H-NRs with a width of 40 nm and length of 1 μm are controlled with ZnO wurtzite structure and grown in [0001] direction. The antimicrobial efficiency of H-NRs was evaluated through experimental assays using a set of microorganisms (Gram-positive Staphylococcus aureus, Bacillus thuriginesis, and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Minimal inhibitory and minimum bactericidal concentrations (MIC and MBC) were determined. These 1D H-NRs exhibited antibacterial activity against all the used strains. The active surface exposure sites of H-NRs play a key role in the strong interaction with the thiol units of vital bacterial enzymes, leading to microbial inactivation. Our finding indicates that the biological effect of the H-NR surface planes on microbial inhibition is decreased in the order of [400]-γ-Al₂O₃ > [100]-β-MnO₂ > [0001]-ZnO geometrics. The lowest key values including MIC (1.146 and 0.250 μg/mL), MBC (1.146, 0.313 μg/mL), and MIC/MFC (0.375 and 0.375 μg/mL) are achieved for [400]-plane γ-Al₂O₃ surfaces when tested against Gram-positive and -negative bacteria, respectively. Among the three H-NRs, the smallest diameter size and length, the largest surface area, and the active exposure [400] direction of γ-Al₂O₃ H-NRs could provide the highest microbial inactivation.

Mechanically Strong, Hydrophobic, Antimicrobial, and Corrosion Protective Polyesteramide Nanocomposite Coatings from Leucaena leucocephala Oil: A Sustainable Resource

The aim of this research work is to develop polyesteramide [LMPEA] nanocomposite coating material [LMPEA/Ag] using N,N-bis(2-hydroxyethyl) fatty amide obtained from non-edible Leucaena leucocephala [LL] seed oil [LLO], and maleic anhydride, reinforced with silver nanoparticles [SNPs], biosynthesized in Leucaena leucocephala leaf extract. UV, XRD, TEM, and particle size analyses confirmed the biosynthesis of NP (37.55 nm). FTIR and NMR established the structure of LMPEA formed by esterification reaction, without any solvent/diluent. Coatings were mechanically strong, well adherent to substrate, flexibility retentive, hydrophobic, and antimicrobial as evident from good scratch hardness (2-3 kg), impact resistance (150 lb per inch), bend test (1/8 inch), high water contact angle measurement value (109°) relative to pristine LMPEA coating (89°), and broad-spectrum antimicrobial behavior against MRSA, P. aeruginosa, E. coli, A. baumannii, and C. albicans. LMPEA and LMPEA/Ag exhibited high corrosion protection efficiencies, 99.81% and 99.94%, respectively, in (3.5% w/v) NaCl solution for 20 days and safe usage up to 200 °C. The synthesized nanocomposite coatings provide an alternate pathway for utilization of non-edible Leucaena leucocephala seed oil through a safer chemical synthesis route, without the use/generation of any harmful solvent/toxic products, adopting "Green Chemistry" principles.

Progress in biomimetic leverages for marine antifouling using nanocomposite coatings

Because of the environmental and economic casualties of biofouling on maritime navigation, modern studies have been devoted toward formulating advanced nanoscale composites in the controlled development of effective marine antifouling self-cleaning surfaces.