Characterization of a “Smart” Hybrid Varnish Electrospun Nylon Benzotriazole Copper Corrosion Protection Coating

Abstract

This work presents the electrochemical evaluation of a proposed copper corrosion protection hybrid coating acting as asmartcorrosion protection system. This consists of an alkyd varnish, painted over electrospun nylon fibers acting as a secondary diffusion barrier and also as a benzotriazole (BTAH) inhibitor nanocontainer. Submicron diameter electrospun nylon 6-6 fiber nanocontainers were prepared from a polymeric solution containing BTAH at different concentrations, and Cu samples were coated with the electrospun fibers and painted over with an alkyd varnish by the drop method. Functional groups in fibers were determined through FTIR spectroscopy. Optical and SEM microscopies were used to characterize the nanocontainer fibers. Samples were evaluated using electrochemical impedance and noise, during six weeks of immersion, in a chloride-ammonium sulfate solution. Excellent response was obtained for thesmartinhibitor coating system. For long periods of immersion good corrosion protection performance was observed. The results presented demonstrate the good barrier properties of the hybrid coating, obstructing the diffusion of aggressive species, through the electrospun structure. Furthermore the nanocontainer functionality to store and liberate the corrosion inhibitor, only when it is needed, was also proved.

Electrospinning: A Powerful Tool to Improve the Corrosion Resistance of Metallic Surfaces Using Nanofibrous Coatings

“…A maximum inhibition efficiency of 83.4% after 5 days of immersion in corrosion media was observed and characterised by electrochemical measurements. [70] also used the same corrosion inhibitor of benzotriazole (BTA) embedded in nylon 6-6 to fabricate electrospun fibres for copper corrosion protection.…”

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion

“…Continuous noise measurements were previously used to study the type of pitting corrosion of the copper covered by organic layers [26]. The pitting index (PI) together with skewness and kurtosis of the time domain data were used to characterize the inhibition corrosion due to organic layers.…”

Smart Protection of Polymer-Inhibitor Doped Systems

“…48,50,51 Electrospinning occurs when the electric force of the solution surface overcomes the surface tension and triggers an electric spark provoking the solution to be expelled from the containing device (syringe) and the jet flow impacts, deposits, and is collected in a metal screen. [53][54][55] The improvements in the electrospinning technique allow production of liquid crystals or other tailored systems and even thinner fibers. [44][45][46][47][48][49][50][51][52] As the jet stretches and dries, radial electrical forces cause it to splash repeatedly, and the fibers dry and solidify.…”

“…19,21 The direct introduction of components of the protective coating inhibitor often leads to the deactivation of the corrosion-inhibitor and polymer matrix degradation. 54 Afterwards, a waterborne alkyd varnish was painted over the electrospun nylon inhibitor (smart) coating, drying at ambient temperature for 24 h. Good adhesion properties are determined after testing. The objective is the possible application of this corrosion protection system to statues or works of art of cultural value, commonly made of copper or its alloys and exposed to atmospheric corrosion conditions.…”