4.Review (3)

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    GRAPHENE OXIDE INTEGRATED INTO PROTECTIVE COATINGS AGAINST CORROSION FOR METALS AND ITS ALLOYS: A REVIEW
    (International Journal of Corrosion and Scale Inhibition, 2022-04-02) Priyanka D; Vinuchakravarthi S; Nalini D; Quraishi M A; Chauhan D S
    This review aims to discuss the effect of graphene oxide (GO) derivatives incorporated protective coatings on various metals against corrosion process in alkaline environments. These coatings increased hydrophobic character and adhesion strength between the coating and metal surface. Electrochemical measurements were used more often among all other techniques to investigate the effect of inhibitor in the polymer matrix (epoxy/silane sol). In some cases, the highest inhibition efficiency was achieved by electrochemically coating GO derivatives on the metal surface. GO derivatives prepared via the adsorption of Pr3+, Ce3+,and Zn2+ ions have revealed a good inhibition tendency for metals in acidic solution because of the exchange of Pr3+, Ce3+, and Zn2+ with those ions (Na+ , Cl–) in the corrosion electrolyte. Further, because of the adsorption of polar groups on GO onto the surface of metals, the hydrophobicity achieved by modified GO coating limits the infiltration of corrosive ions and enhances inhibitory efficiency. And, scratches were foreseen during the manufacturing of coatings on metallic substrates, and this harms the organic coatings. The defect created by impurities developed coatings deterioration that was prone to the diffusion of corrosive substances, severely reducing the coatings’ lifespan. Grafting graphene oxide with various functional groups was used to achieve self-healing behavior in organic coatings. At the defective site of the metallic substrates, self-healing by functionalized graphene oxide created dense protective coatings.
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    PREPARATION AND CHEMICAL/PHYSICAL CHARACTERIZATION OF INDIVIDUAL NANOSCALED FIBRILS
    (Bentham Science Publishers, 2022) Praveetha, Senthilkumar; Sharmila, Chandran; Alexey, Kartsev; Vladimir, Shavrov; Petr, Lega
    Polymer-based nanofibril finds its application in various fields including tissue engineering, environmental monitoring, food packaging, and micro/nanoelectromechanical systems. These nanofibrils are subjected to chemical treatment and constant stress, which may cause permanent deformation to the fibrils when it is used. Therefore, the synthesis of well-defined nanofibrils and characterization techniques are key elements in identifying desired chemical and physical properties for suitable applications. Many methods have been developed to prepare individual nanofibrils, including electrospinning, phase separation, template synthesis, and self-assembly. Among all, self-assembly offers simple, efficient, and lowcost strategies that produce high-ordered nanofibrils using noncovalent interactions including hydrogen bonding, electrostatic interactions, π-π interactions, and hydrophobic interactions. The first part of the review provides detailed molecular interactions and simulations that can be controlled to achieve the formation of well-defined individual nanofibrils. The second part of the review describes the various existing tools to characterize the chemical and physical properties of single nanofibrils including atomic force microscopy. In the final part of the review, recently developed novel nanotools that measure the mechanical properties of nanofibrils are described. By bridging the gap between molecular interactions and resulting nanoscale fibirls, physical and chemical properties may lead to the construction of novel nanomaterials in the area of nanoscience and nanotechnology.
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    A CRITICAL REVIEW ON EXTRACTION AND ANALYTICAL METHODS OF PHTHALATES IN WATER AND BEVERAGES
    (Elsevier, 2022-07-19) Amritha, P S; Veena, Vinod; Harathi, P B
    Phthalates (PAEs) are the class of lipophilic chemicals, which are used as additives in the manufacturing of plastics. It results in presence of PAEs in water and beverages because of their migration capacity. Their presence has attracted considerable attention due to their potential impacts on ecosystem functioning and public health. In addition, an enormous number of research articles have been published between 2000 and 2020, which have been identified and their results have been tabulated displaying PAEs analyzed, matrices, sample preparation, analytical method used, the limit of detection (LOD), and recovery percentages. Numerous sample preparation and analytical methods are found which are suitable for the reliable determination of the PAEs. The analysis of the PAEs is difficult due to their ubiquitous presence and their complexity, therefore suitable precautions, should be taken into account. In this review, we provide an overview of various pre-treatment measures and detection methods for PAEs in several types of water and beverages, mainly focusing on the last 20 years published works have been discussed. Pre-treatment methods mainly include liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME), liquid-phase microextraction (LPME), and many more rare techniques. Chromatographic and non-chromatographic techniques coupled with or without diodes, spectrophotometers, and detectors, have been described. The concept of “green analytical chemistry” for PAE determination has also been discussed. Hereby, the limitations and challenges in these applications are also included.