Double-layer peelable coating with eminent mechanical properties and anti-permeability

Abstract

The inferior resistance to liquid permeation is a typical drawback of common peelable coatings, which can not only shorten their service life under the liquid environments, but also restrict their large-scale application in this field. To solve these problems, a scheme of double-layer composite coating has been proposed by incorporating two typical one-component coatings and its effect on the improvement of the anti-permeability of original peelable coating was investigated. The results revealed that the Double-Layer Peelable Coating (DLPC) exhibited an optimal comprehensive performance on both flexibility and anti-permeability, which can be applied on a variety of different substrate surfaces (such as metals, woods and glasses etc.).Then the evolution of the mechanical properties of the coatings under continuous immersion in 3.5 wt% NaCl solution was tracked by peel and tensile tests, and the anti-permeability was also monitored using electrochemical impedance spectroscopy (EIS) technology and water absorption test. The results demonstrated that although the mechanical properties and anti-permeability of both peelable coatings deteriorated with the extension of immersion time, their response trends were obviously different. The service life of the DLPC has increased by about 648 h compared with the mono-layer peelable coating. Besides, the results of resistance to acids, alkalis aqueous solutions and neutral salt spray also verified the effectiveness of double-layer composite coating.