N-Methylaniline is an organic compound serves as an important intermediate in organic synthesis, acid absorber, and solvent. Recent studies have shown that it can be used to form electropolymer composite coatings on copper surfaces.
Destruction of the passivation film on the copper surface shortens the life of related facilities
Copper alloys are widely used in many manufacturing fields such as industrial heat exchange and electronic device assembly due to their good ductility and thermal/electrical conductivity. However, harsh environments (such as Cl-containing media) will destroy the passivation film on the copper surface and then corrode the metal substrate, seriously threatening the performance and life of related facilities. Even worse, the release of cupric and/or cuprous species into ecosystem also poses a severe biologic issue threatening the environmental security. Electropolymerization (ECP) can form a thin layer of conductive polymer in situ on the metal surface, and exerts excellent protection on the substrate through anodic protection and physical shielding. Under normal circumstances, the active metal surface must undergo a passivation step before forming an electropolymer coating through ECP to provide a stable interface, which indirectly limits the in-situ generation and action advantages of ECP.
Recently, conductive polymers (CPs) have attracted widespread attention in coating fabrication for the tunable conductivity and high protection efficiency. Compared with the conventional chemical route for preparing CPs, electrochemical strategy (electropolymerization) via the redox of organic precursors gains great focus in polymer science, which leads to the in-situ formation of protective coatings on metal substrate such as polyaniline (PANI) and polypyrrole (PPy). It has been manifested that CPs prohibit the establishment of galvanic couple between local anodes and cathodes for their anodic protection and electron mediation abilities. Although earning several benefits in corrosion inhibition, pristine electropolymerized coatings also suffer from certain limitations such as porous structure, inferior dimensional stability and low mechanical integrity. Besides, recent achievements documented that pristine conductive coatings hardly exert long-term protection for metals in aggressive media. On the contrary, there is a rising demand for enhancing the durability of coatings employed in diversified environments. Hence, tailoring CPs to guarantee their protective performance for metals has been a challenge of both academic and industrial concerns.
In view of this, Fan Baomin of Beijing Technology and Business University and others introduced Zhidon salt to form a long-lasting protective ECP layer of poly(N-methylaniline)/sodium phosphate on the copper surface in one step, which can achieve in-situ repair of damaged coatings; in multi-scale theory On the basis of simulation, the concept of using time-domain and spatial diffusion trajectories to evaluate the protective performance of coatings is proposed. Under different interaction summations (electrostatic force and van der Waals force), the behavior of specific tracer targets in the coating at different stages is visually described. Diffusion behavior, and then obtain the failure mechanism of the coating during service. The relevant research results are titled Long-term protective mechanism of poly(N-methylaniline)/phosphate one-step electropolymerized coatings for copper in 3.5% NaCl solution and were published in the internationally renowned journal "Journal of Alloys and Compounds".
BLOOM Tech N-Methylaniline is produced using state-of-the-art technology and strict manufacturing processes, ensuring its purity and consistency. This allows for reliable performance in a wide range of applications, whether it's used in the chemical industry, pharmaceuticals, dyes, or other fields.
We prioritize the safety of our products. Our N-Methylaniline undergoes rigorous testing to ensure it meets the highest safety standards, minimizing any potential risks associated with its use.
 |
 |
Long-term protective mechanism of poly(N-methylaniline)/phosphate one-step electropolymerized coatings for copper in 3.5% NaCl solution
Through an electrochemically easy-to-operate ion doping process, different contents of sodium phosphate (1 mM, 5mM, 10 mM) are doped into N-methylaniline solution, and poly(N-methylaniline) is formed in situ on the copper surface in one step. aniline)/sodium phosphate electropolymer composite coating. By evaluating physical properties such as density, conductivity, and adhesion strength, the optimal preparation process is clarified and used as the target for subsequent research and analysis.
The morphology and electrochemical analysis of the coatings after soaking in 3.5% NaCl solution for different periods of time were conducted. Morphology analysis shows that the PNMA-5P composite coating maintains its original morphology after immersion for 30 days, and still has good stability and hydrophobicity, thus effectively reducing the concentration of copper ions released into the bulk solution. Electrochemical tests show that the doped phosphate can maintain the anodic protection of the PNMA layer, prevent corrosive substances from entering the copper layer, and stabilize the corrosion current density at a lower level. Furthermore, the charge transfer resistance of PNMA-5P coated specimens significantly increases the electron-mediating capability of the copper/coating interface. Composite coatings have good electrochemical blocking effects due to their dense structure (low porosity). Doped phosphates conduct electricity to densify the coating, maintain anodic protection, enhance the barrier effect and ultimately improve the corrosion resistance of the underlying substrate.
Multiscale theoretical calculations show that phosphate stabilizes between PNMA chains through electrostatic forces and promotes parallel deposition of the polymer on the copper surface. The time-domain and spatial diffusion trajectories of in-situ ions indicate differences in the diffusion behavior of corrosive ions in the two models: corrosive ions in PNMA have an expanded diffusion trajectory and show a tendency to migrate across the coating; while in-situ corrosive ions in the composite coating have an expanded diffusion trajectory. The movement of ions is restricted to a local area. The composite coating hinders ion diffusion and slows down the transmission of ions inside the coating, significantly inhibiting the corrosion of metal by the corrosive medium, which is consistent with the experimental results. Composite coatings benefit from a dense structure, good barrier and anodic protection, providing excellent long-term protection for the substrate.
Chemicals and solutions
NMA was supplied by Shaanxi BLOOM Tech Co., Ltd (Xi'an, China), which was bi-distilled and darkly kept at 270 K before utilization. Analytical Na3PO4, NaCl, HNO3 and H2SO4 solutions and absolute ethanol were obtained from Innochem Company (Beijing, China) and used without further purification. Copper sheets (99.9%) were purchased from Tianjin Chemical Institute (China).