The (EDTA)4− organic substituents were supplemented with alkaline silicates electrolyte, however in varying concentration to explore the microstructure, chemical composition and subsequent effects on the biodegradation of the PEO coated Mg AZ91 alloy. From surface analysis-, carried out through SEM, samples with zero-(EDTA)4− were found-, lacking pancake structural features; however, supplementing electrolyte with (EDTA)4−, bulky and layered pancakes were obtained with minimum cracks and minimum porosity for EDT-1. From the phase and inner layer analysis, it was found that EDTA can significantly alter the surface layers composition and could act as a passivation agent-; however, individual polycrystalline phases were not found to form. The hardness value obtained for EDT-1 was ∼909.69 HV, the highest value found here which occurs with the shallowest indents found in this study. In-vitro degradation analysis was carried out using potentiodynamic polarization at room temperature, cyclic polarization at RT and high fever conditions (HFT ∼40 °C). The corrosion potential for coated AZ91 was obtained as a positive value of ∼ 0.1 V, for the first time in the PEO research; however, the results were not supported by the cyclic polarization tests at room temperature and at HFT. The post corrosion microstructural analysis confirmed the effective role of EDTA up to 1.0 g·L−1 and revealed the formation of thin films during the forward polarization at HFT.

In this work, poly(acrylic acid)-based layers were injected to form a sandwich layer between the cationic and anionic species for a compact and effective fire-retardant coating on cotton fabric using the layer-by-layer coating technique. From the SEM analysis, as the number of tri-layers increases, the attachment intensity increases, as can be seen for poly(acrylic acid) chitosan and bentonite clay PCB-5TL (the highest tri-layers), while in the case of halloysite-based coatings, as the number of tri-layers increases, instead of attachment, the agglomeration increases due to the high surface area of halloysite nanoclay tubes. FTIR and UV confirmed the finding from the new peak entry and an increase in thickness. The highest thermal residue, ~18%, was obtained for poly(acrylic acid) chitosan and halloysite nanoclay PCH-5TL with a maximum degradation peak intensity at ~389 °C. From the flammability and after-burning SEM investigation test, it was observed that the halloysite-based coating with a higher number of layers offered higher resistance against the flame spread and ignition and, thus, produced a higher amount of char.

Porous organic polymers (POPs) were synthesized by polymerization of benzene triamine and trimesoyl chloride. The POP material is water-stable and shows selective extraction of Cu(ii) due to its intrinsic nitrogen-rich surface, which forms a chelate with Cu(ii) ions. The prepared polymeric material was characterized through Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray elemental mapping, and scanning electron microscopy for surface group analysis and structural morphology studies. A microcolumn was developed using POPs for the preconcentration of trace Cu(ii) from complex real samples. The proposed method shows a high enrichment factor of 900 and a quantification limit of 1.1 ppb for Cu(ii) ions. The accuracy of the developed method was confirmed by analyzing standard reference materials (NIES 8 and NIES 10c) and the standard addition method. The method shows good precision with an RSD value of less than 5%.