Protection of stainless steel by the electrodeposition of polyaniline/poly(o-phenylenediamine) composite layers

Three polyaniline (PANI)/poly(o-phenylenediamine) (PoPD) mixtures have been electrochemically deposited on a stainless steel surface from an acidic solution. Electrocopolymerization was favorable at high molar ratios of aniline to o-phenylenediamine, and the resulting copolymer is a random type. Two bilayers, PoPD/PANI and PANI/PoPD, were prepared by successive electrodeposition, during which different multiphase structures were obtained. The presence of PoPD with PANI in the copolymer or multilayer structures enhances the passivation of the SS. The bi-layer coating in which a PANI layer lies under the PoPD produced the best passive oxide on the SS. The resistance to pitting increases with the coating order as follows: PANI < copolymer ? PANI/PoPD < PoPD < PoPD/PANI.     

A comparative study on poly (methoxy/amino) aniline: effect of monomer feed ratio of copolymers and bilayers on stainless steel protection

Journal of Solid State Electrochemistry - Homopolymers, copolymers, and bilayers of polyaniline (PANI), with both poly(o-aminoaniline) (POAA) and poly(o-methoxyaniline) (POMA), were synthesized...     

Molecular Interaction Studies and Phytochemical Characterization of Mentha pulegium L. Constituents with Multiple Biological Utilities as Antioxidant,Antimicrobial, Anticancer and Anti-Hemolytic Agents

Multiple biological functions of Mentha pulegium extract were evaluated in the current work. Phytochemical components of the M. pulegium extract were detected by Gas Chromatography-Mass Spectrometry (GC-MS) and High-performance liquid chromatography (HPLC). Moreover, M. pulegium extract was estimated for antioxidant potential by 2,2-Diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical scavenging, antimicrobial activity by well diffusion, and anticoagulant activity via prothrombin time (PT) and activated partial thromboplastin time (APTT). GC-MS analysis detected compounds including cholesterol margarate, stigmast-5-en-3-ol, 19-nor-4-androstenediol, androstan-17-one, pulegone-1,2-epoxide, isochiapin B, dotriacontane, hexadecanoic acid and neophytadiene. Chrysoeriol (15.36 µg/mL) was followed by kaempferol (11.14 µg/mL) and 7-OH flavone (10.14 µg/mL), catechin (4.11 µg/mL), hisperdin (3.05 µg/mL), and luteolin (2.36 µg/mL) were detected by HPLC as flavonoids, in addition to ferulic (13.19 µg/mL), cinnamic (12.69 µg/mL), caffeic (11.45 µg/mL), pyrogallol (9.36 µg/mL), p-coumaric (5.06 µg/mL) and salicylic (4.17 µg/mL) as phenolics. Antioxidant activity was detected with IC₅₀ 18 µg/mL, hemolysis inhibition was recorded as 79.8% at 1000 μg/mL, and PT and APTT were at 21.5 s and 49.5 s, respectively, at 50 μg/mL of M. pulegium extract. The acute toxicity of M. pulegium extract was recorded against PC3 (IC₅₀ 97.99 µg/mL) and MCF7 (IC₅₀ 80.21 µg/mL). Antimicrobial activity of M. pulegium extract was documented against Bacillus subtilis, Escherichia coli, Pseudomonas aureus, Candida albicans, Pseudomonas aeruginosa, but not against black fungus Mucor circinelloides. Molecular docking was applied using MOE (Molecular Operating Environment) to explain the biological activity of neophytadiene, luteolin, chrysoeriol and kaempferol. These compounds could be suitable for the development of novel pharmacological agents for treatment of cancer and bacterial infections.