Abstract:Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL) and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

Multipurpose gel beads prepared from natural or synthetic polymers have received significant attention in various applications such as drug delivery, coatings, and electrolytes because of their versatility and unique performance as micro- and nanocontainers.1 However, comparatively little work has been done on poly(ionic liquid)-based materials despite their unique ionic characteristics. Thus, in this contribution we report the facile preparation of polymerizable ionic liquid-based gel beads using thiol-ene click chemistry. This novel system incorporates pentaerythritol tetra (3-mercaptopropionate) (PETKMP) and 1,4-di(vinylimidazolium) butane bisbromide in a thiol-ene-based photopolymerization to fabricate the gel beads. Their chemical structure, thermal and mechanical properties have been investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The gel beads possess low Tg and their ionic functionalities attribute self-healing properties and their ability to uptake small molecules or organic compounds offers their potential use as pH sensing material and macrocontainers.

Polyionic liquid based gels have stimulated significant interest due to their wide applications in flexible electronics, such as wearable electronics, roll-up displays, smart mobile devices and implantable biosensors. Novel supported liquid gel electrolyte using polymerisable ionic liquid and an acrylate monomer, has been developed in this work by entrapping ionic liquid during polymerisation instead of post polymerisation impregnation. The chemically crosslinked polyionic liquid gel electrolyte (PIL) is prepared using 2-hydroxyethylmethacrylate (HEMA) monomer and a polymerisable ionic liquid, 1,4-di(vinylimidazolium)butane bisbromide (DVIMBr) in an ionic liquid (IL- 1-butyl-3 methylimidazolium hexafluorophosphate) as the polymerisation solvent, which resulted in in-situ entrapment of the IL in the gel during polymerisation and crosslinking of the polymer. The supported liquid gel electrolyte (SLG) material was characterised with thermal analysis, infrared spectroscopy, and dynamic mechanical analysis, and was found to be stable with good mechanical properties. The electrochemical analysis showed that these chemically cross-linked PIL gel electrolyte-supported ILs are suitable for solid-state, flexible supercapacitor applications.

In this contribution, we report the facile preparation of cross-linked polymerizable ionic liquid (PIL)-based nanoparticles via thiol–ene photopolymerization in a miniemulsion. The synthesized PIL nanoparticles with a diameter of about 200 nm were fully characterized with regard to their chemical structures, morphologies, and properties using different techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. To gain an in-depth understanding of the physical and morphological structures of the PIL nanoparticles in an emulsion, small-angle neutron scattering and ultra-small-angle neutron scattering were used. Neutron scattering studies revealed valuable information regarding the formation of cylindrical ionic micelles in the spherical nanoparticles, which is a unique property of this system. Furthermore, the PIL nanoparticle emulsion was utilized as an inhibitor in a self-assembled nanophase particle (SNAP) coating. The corrosion protection ability of the resultant coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that the PIL nanoparticle emulsion in the SNAP coating acts as an inhibitor of corrosion and is promising for fabricating advanced coatings with improved barrier function and corrosion protection.

A novel hybrid anticorrosion coating with dual network of inorganic (Si-O-Si) and organic bonds (C-S-C) was prepared on metal through an in situ sol-gel and thiol-ene click reaction. This novel interfacial thin film coating incorporates (3-mercaptopropyl) trimethoxysilane (MPTS) and 1,4-di(vinylimidazolium) butane bisbromide based polymerizable ionic liquid (PIL) to form a thiol-ene based photo-polymerized film, which on subsequent sol-gel reaction forms a thin hybrid interfacial layer on metal surface. On top of this PIL hybrid film, a self-assembled nanophase particle (SNAP) coating was employed to prepare a multilayer thin film coating for better corrosion protection and barrier performance. The novel PIL hybrid film was characterised for structure and properties using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The corrosion protection performance of the multilayer coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results reveal that this novel double layer coating on metal offers excellent protection against corrosion and has remarkably improved the barrier effect of the coating.

The synthesis, NMR spectroscopy, single-crystal X-ray structure, and solution electrochemistry of the new compound [2,6-{CH(CH3)}2C6H3]3 As, abbreviated as Dipp3As, is reported. The molecule, prepared by reaction of AsCl3 with a pre-formed aryl copper reagent, Dipp4Cu4, crystallizes in the hexagonal space group R3 as a racemic twin. The sum of angles around As, ∑∠{CAsC}, is 329.13(3)° in the X-ray structure and 329.17° from an R-B3LYP/6-31G(d,p) hybrid density functional theory calculation. The aromatic rings are quite distorted with both the ipso carbon and especially the As atom significantly out of plane by 0.503(3) Å. The ambient temperature NMR spectrum fits for C3 symmetry implying that inversion is slow on the NMR timescale. Cyclic voltammetry on a glassy carbon electrode in CH2Cl2 with 0.4 M [nBu4N][PF6] over scan rates of 0.05–0.8 V s–1 and temperatures of 22 ± 2°C produced one quasi-reversible process with Em1 = +0.43 V at a scan rate of 0.20 V s–1 and a second irreversible process with a peak potential of +1.45 V (v. Fc+/0). The diffusion coefficient has been measured as 3.3 ± 0.1 × 10–6 cm2 s–1 in CH2Cl2 solution containing 0.4 M [nBu4N][PF6]. Chemical oxidation with AgPF6 in CH2Cl2 in degassed solutions in sealed vessels allowed for recording of characteristic EPR spectra; at 293 K, a (75As) = 26.1 mT and g = 2.021. In frozen solution, an almost isotropic spectrum is obtained (g║ = 2.000 mT and g⊥ = 2.003 mT) and the hyperfine splitting constants are a║ = 47.9 and a⊥ = 19.0 mT, leading to an estimate for the structure being slightly pyramidal with ∑∠{CAsC} ≈ 351°.

Density functional theory (DFT) calculations for the six-membered ring 1,4-(CH

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