Electrochemical Characterization of Polymeric Coatings for Corrosion Protection: A Review of Advances and Perspectives

A curcumin quantum dot blended polyacrylonitrile electrospun nanofiber coating on 316 L SS for improved corrosion resistance in the marine environment

Corrosion of 316 L SS is a significant global concern and recently polymeric nanofibers have been gaining attention for their potential in enhancing the corrosion resistance of metals. In this work, an electrospinning technique was deployed for the deposition of a curcumin quantum dot (CMQD) blended polyacrylonitrile (PAN) nanofibrous anticorrosive coating on 316 L SS. The optimized PAN-CMQD coated samples obtained from the weight loss studies were examined to assess their corrosion inhibition characteristics in 3.5 wt% NaCl electrolyte as the corrosion environment using potentiodynamic polarization and electrochemical impedance spectroscopy. The PAN-CMQD coated samples showed two-order reduction in I corr compared to the uncoated 316 L SS. The results of the long-term analysis for 30 days revealed no significant changes in I corr and E corr values and no pit formation for PAN-CMQD coated samples, proving the longevity of the coating. Thus, this work will serve as a cost-effective futuristic strategy for the large-scale development of anticorrosive nanofibrous coatings for enhancing the corrosion resistance behavior of metals and alloys in various industrial sectors.

A Multi-Objective Optimization of Neural Networks for Predicting the Physical Properties of Textile Polymer Composite Materials

This paper explores the application of multi-objective optimization techniques, including MOPSO, NSGA II, and SPEA2, to optimize the hyperparameters of artificial neural networks (ANNs) and support vector machines (SVMs) for predicting the physical properties of textile polymer composite materials (TPCMs). The optimization process utilizes data on the physical characteristics of the constituent fibers and fabrics used to manufacture these composites. By employing optimization algorithms, we aim to enhance the predictive accuracy of the ANN and SVM models, thereby facilitating the design and development of high-performance textile polymer composites. The effectiveness of the proposed approach is demonstrated through comparative analyses and validation experiments, highlighting its potential for optimizing complex material systems.

Study on the Effect of Additives on the Performance of Cement-Based Composite Anti-Corrosion Coatings for Steel Bars in Prefabricated Construction

The influence of polymer emulsion, pigment filler, and dispersant on the corrosion resistance of polymer cement-based composite anti-corrosion coatings were investigated in this study. Adhesion loss rate tests and electrochemical tests were conducted on samples. The research results show that optimal corrosion resistance can be achieved with a 45 wt% dosage of emulsion, a 6 wt% dosage of pigment filler, and a 0.30 wt% dosage of dispersant. The bonding properties of bare steel bars, epoxy-coated steel bars, and polymer cement-based composite anti-corrosion coated steel bars with grout were compared. The results show that the polymer cement-based composite anti-corrosion coating can enhance the bonding properties of the samples. Furthermore, the microscopic analysis was conducted on the samples. The results demonstrate that the appropriate addition of emulsion can fill internal pores of the coating, tightly bonding hydration products with unhydrated cement particles. Moreover, incorporating a suitable dosage of functional additives enhances the stability of the coating system and leads to a denser microstructure.

Cr-Free Anticorrosive Primers for Marine Propeller Applications

Marine propellers work under severe service conditions, where they commonly suffer from mechanical, electrochemical, and biological corrosion damage. The major mechanical corrosion involves cavitation, erosion, and impingement corrosion. On the other hand, the major electrochemical corrosion involves galvanic corrosion and electrolysis. As a result, consideration of both desired mechanical and electrochemical properties is necessary when designing a marine propeller coating. In this study, a PVB (polyvinyl butyral) and an epoxy coating were formulated without corrosion inhibitors to investigate the desired coating properties for marine propeller applications. The two coatings were compared with a Cr-containing commercial marine propeller coating to investigate the advantages and disadvantages of using PVB and epoxy for marine propeller coatings. It was found that it is desirable for marine propeller coatings to be flexible to avoid cracking and flaking; to be able to withstand high pH in order to resist cathodic disbondment (electrolysis); to have adequate primer-substrate adhesion; and, ideally, to be able to self-heal when the coating is damaged (cavitation). It was found that the PVB-ZO coating has more desirable properties, and introducing self-healing properties could be one of the options for further optimization in the future.

A facile approach to create sensitive and selective Cu(ii) sensors on carbon fiber microelectrodes

A facile platform derived from deposition of ethynyl linkers on carbon fiber microelectrodes has been developed for sensitive and selective sensing of Cu(ii). This study is the first to demonstrate the successful anodic deposition of ethynyl linkers, specifically 1,4-diethynylbenzene, onto carbon fiber microelectrodes. Multi-scan deposition of DEB on these microelectrodes resulted in an increased sensitivity and selectivity towards Cu(ii) that persists amidst other divalent interferents and displays sustained performance over four days while stored at room temperature. This method can be extended to other ethynyl terminal moieties, thereby creating a versatile chemical platform that will enable improved sensitivity and selectivity for a new frontier of biomarker measurement.

A Review of Electrochemical Techniques for Corrosion Monitoring - Fundamentals and Research Updates

Interculturally, corrosion has been counted as one of the most expensive factors toward the retrogression of concrete and metallic structures resulting in huge monetary losses and unanticipated loss of life. To a large extent, corrosion-related catastrophes can be avoided by having the ability to monitor corrosion before structural integrity is jeopardized. This paper critically reviews the various accustomed electrochemical techniques utilized for corrosion monitoring in terms of their definition, timeline, experimental set-up, advantages, and shortcomings. Additionally, literature exploiting these techniques as their corrosion detection technique has been focused on here. Furthermore, a comparison between recently reported methods has been made to provide better insights into the research progress in this arena.

Visualizing Penetration of Fluorescent Dye through Polymer Coatings

Understanding how small molecules penetrate and contaminate polymer films is of vital importance for developing protective coatings for a wide range of applications. To this end, rhodamine B fluorescent dye is visualized diffusing through polystyrene-polydimethylsiloxane block copolymer (BCP) coatings using confocal microscopy. The intensity of dye inside the coatings grows and decays non-monotonically, which is likely due to a combination of dye molecule transport occurring concurrently in different directions. An empirical fitting equation allows for comparing the contamination rates between copolymers, demonstrating that dye penetration is related to the chemical makeup and configuration of the BCPs. This work shows that confocal microscopy can be a useful tool to visualize the transport of a fluorophore in space and time through a coating.

The Effect of Mechanical Pretreatment on the Electrochemical Characteristics of PEO Coatings Prepared on Magnesium Alloy AZ80

The main objective of this article is to provide new information on the effects of mechanical pretreatment of AZ80 magnesium alloy ground with SiC emery papers of different grain sizes on the plasma electrolytic oxidation (PEO) process and corrosion properties of AZ80 in 0.1 M NaCl solution. Then, the roughness of the coated samples was measured by confocal microscopy. The corrosion properties of the ground and coated surfaces were determined by potentiodynamic polarization (PDP) within 1 h of exposure, and electrochemical impedance spectroscopy (EIS) was performed during 168 h of exposure at laboratory temperature. Consequently, the obtained results of the PDP measurements were evaluated by the Tafel analysis and the EIS evaluation was performed by the equivalent circuit analysis through Nyquist diagrams. The morphology and structure of PEO coatings were observed by scanning electron microscopy (SEM) through the secondary imaging technology, and the presence of certain elements in PEO coatings was analyzed by EDS analysis.

A Label-Free and Antibody-Free Molecularly Imprinted Polymer-Based Impedimetric Sensor for NSCLC-Cells-Derived Exosomes Detection

In this study, a label-free and antibody-free impedimetric biosensor based on molecularly imprinting technology for exosomes derived from non-small-cell lung cancer (NSCLC) cells was established. Involved preparation parameters were systematically investigated. In this design, with template exosomes anchored on a glassy carbon electrode (GCE) by decorated cholesterol molecules, the subsequent electro-polymerization of APBA and elution procedure afforded a selective adsorption membrane for template A549 exosomes. The adsorption of exosomes caused a rise in the impedance of the sensor, so the concentration of template exosomes can be quantified by monitoring the impedance of GCEs. Each procedure in the establishment of the sensor was monitored with a corresponding method. Methodological verification showed great sensitivity and selectivity of this method with an LOD = 2.03 × 10³ and an LOQ = 4.10 × 10⁴ particles/mL. By introducing normal cells and other cancer cells derived exosomes as interference, high selectivity was proved. Accuracy and precision were measured, with an obtained average recovery ratio of 100.76% and a resulting RSD of 1.86%. Additionally, the sensors' performance was retained at 4 °C for a week or after undergoing elution and re-adsorption cycles seven times. In summary, the sensor is competitive for clinical translational application and improving the prognosis and survival for NSCLC patients.

Computational Foretelling and Experimental Implementation of the Performance of Polyacrylic Acid and Polyacrylamide Polymers as Eco-Friendly Corrosion Inhibitors for Copper in Nitric Acid

Copper is primarily used in many industrial processes, but like many other metals, it suffers from corrosion damage. Polymers are not only one of the effective corrosion inhibitors but also are environmentally friendly agents in doing so. Hence, in this paper, the efficacy of two polyelectrolyte polymers, namely poly(acrylic acid) (PAA) and polyacrylamide (PAM), as corrosion inhibitors for copper in molar nitric acid medium was explored. Chemical, electrochemical, and microscopic tools were employed in this investigation. The weight-loss study revealed that the computed inhibition efficiencies (% IEs) of both PAA and PAM increased with their concentrations but diminished with increasing HNO₃ concentration and temperature. The results revealed that, at similar concentrations, the values of % IEs of PAM are slightly higher than those recorded for PAA, where these values at 298 K reached 88% and 84% in the presence of a 250 mg/L of PAM and PAA, respectively. The prominent IE% values for the tested polymers are due to their strong adsorption on the Cu surface and follow the Langmuir adsorption isoform. Thermodynamic and kinetic parameters were also calculated and discussed. The kinetics of corrosion inhibition by PAA and PAM showed a negative first-order process. The results showed also that the used polymers played as mixed-kind inhibitors with anodic priority. The mechanisms of copper corrosion in nitric acid medium and its inhibition by the tested polymers were discussed. DFT calculations and molecular dynamic (MD) modelling were used to investigate the effect of PAA and PAM molecular configuration on their anti-corrosion behavior. The results indicated that the experimental and computational study are highly consistent.