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Studies of the Self-Assembled Films of a Heterocyclic Compound Containing Nitrogen and Schiff Bases on Iron and 20# Steel Surface

Author: ZhouJuanJuan
Tutor: ChenShenHao
School: Shandong University
Course: Physical and chemical
Keywords: Iron Self-assembled monolayer Thiadiazole Schiff base Electrochemical impedance spectroscopy
CLC: TG174.4
Type: Master's thesis
Year: 2008
Downloads: 126
Quote: 3
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Abstract

In this thesis, the different types of organic molecules on the surface of iron or steel 20 # SAMs. Use of EIS, polarization curves of the self-assembled monolayer of iron or steel in acidic solution corrosion inhibition; utilization XPS, FT-IR, SEM, EDS characterization of self-assembled monolayers of iron surface chemical composition and surface morphology; using quantum chemical calculations and molecular simulation of the self-assembled film and the metal substrate bonding state, adsorption configuration, arrangement and other microscopic properties have been studied theoretically for the self-assembled monolayer formation mechanism to provide relevant supporting information. The main findings of this thesis includes the following two aspects: 1. The iron electrode, 20 # steel electrodes 2 - mercapto-5 - methyl-1 ,3,4 - thiadiazole (McMT) ethanol assemble different time to form self-assembled monolayers using electrochemical methods and surface analysis techniques SAMs were characterized by various properties. EIS results show that with the growth of the electrode immersion time, SAMs inhibition efficiency increases. 20 # steel, iron and polarization curves can be seen that the experimental results, the formation of self-assembled monolayer while suppressing iron anode and cathode during the process. After assembly the overall electrode polarization curve moves to the low current region, the corrosion current also with immersion time increases. XPS, SEM / EDS experimental results demonstrate McMT molecular self-assembly film formation. In addition, the use of quantum chemical calculations and molecular modeling studies McMT molecules in two conjugated forms (keto mercaptan and sulfur) in the Fe (110) surface structure of self-assembled monolayers and molecular dynamics results show that McMT iron molecule is almost flat on the surface, and in the present experimental conditions, the thiol form more stable. 2 Synthesis of Schiff bases of four molecules, namely N, N'-bis (2,6 - dimethylphenyl) ethylene imine (SB-1), N, N'-bis (2,6- - diisopropylphenyl) ethylene imine (SB-2), N, N'-bis (2,6 - dimethylphenyl)-1.2-dimethyl-ethylene imine (SB-3) , N, N'-bis (2,6 - diisopropylphenyl) -1,2 - dimethyl-ethylene imine (SB-4), and the surface of the iron electrode was prepared from the Schiff base of the four assembled monolayers. Using FT-IR characterization of self-assembled monolayer formation. Four kinds of Schiff base molecule functional groups characteristic absorption peak, the \. It can be seen Schiff base molecules adsorbed on the iron surface, and the interaction between lead and iron absorption peaks red shift. Using EIS and polarization curves of the Schiff base self-assembled monolayer on iron electrode in 0.5 mol · dm ^{-3 of H ₂ SO ₄ solution inhibition efficiency. The results show that four kinds of Schiff base self-assembled monolayer can effectively inhibit the iron corrosion in sulfuric acid solution, and the inhibition efficiency increases with the increase in the growth of assembly time. The four Schiff base iron surface self-assembled monolayer inhibition efficiency in the order of SB-1> SB-3> SB-2> SB-4. Molecular dynamics simulation results show that, SB-1 molecules on Fe (110) surface adsorption, most of the molecules are lying on the iron surface. The other three elements, some of molecules on the surface of the irregularly arranged, which causes defects in the self-assembled film increased. Not dense self-assembled films will make it easier for aggressive particles near the surface of iron through and causing corrosion. In addition, the radial distribution function calculation results and electrochemical tests showed four inhibition efficiency of self-assembled monolayers results are consistent with the size of the order.}

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metal corrosion protection,metal surface treatment > Corrosion control and protection > Metal surface protection technology
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