D'Elia Marco F, Magni Mirko, Romanò Thomas, Trasatti Stefano P M, Niederberger Markus, Caseri Walter R
Laboratory for Multifunctional Materials, Department of Materials, ETH Zürich, 8093 Zürich, Switzerland.
Department of Environmental Science and Policy, Universitá degli Studi di Milano, 20133 Milan, Italy.
Polymers (Basel). 2022 Aug 24;14(17):3457. doi: 10.3390/polym14173457.
Poly(phenylene methylene) (PPM) is a multifunctional polymer featuring hydrophobicity, high thermal stability, fluorescence and thermoplastic processability. Accordingly, smart corrosion resistant PPM-based coatings (blend and copolymer) were prepared and applied by hot pressing on aluminum alloy AA2024. The corrosion protection properties of the coatings and their dependence on coating thickness were evaluated for both strategies employed. The accelerated cyclic electrochemical technique (ACET), based on a combination of electrochemical impedance spectroscopy (EIS), cathodic polarizations and relaxation steps, was used as the main investigating technique. At the coating thickness of about 50 µm, both blend and copolymer PPM showed effective corrosion protection, as reflected by |Z| of about 10 Ω cm over all the ACET cycles. In contrast, when the coating thickness was reduced to 30 µm, PPM copolymer showed neatly better corrosion resistance than blended PPM, maintaining |Z| above 10 Ω cm with respect to values below 10 Ω cm of the latter. Furthermore, the analysis of many electrochemical key features, in combination with the optical investigation of the coating surface under 254 nm UV light, confirms the intrinsic self-healing ability of the coatings made by PPM copolymer, contrary to the reference specimen (i.e., blend PPM).
聚亚苯基亚甲基（PPM）是一种具有疏水性、高热稳定性、荧光性和热塑性加工性能的多功能聚合物。因此，制备了基于PPM的智能耐腐蚀涂层（共混物和共聚物），并通过热压工艺涂覆在AA2024铝合金上。针对所采用的两种策略，评估了涂层的耐腐蚀性能及其对涂层厚度的依赖性。基于电化学阻抗谱（EIS）、阴极极化和弛豫步骤相结合的加速循环电化学技术（ACET）被用作主要研究技术。在涂层厚度约为50 µm时，共混PPM和共聚PPM均表现出有效的腐蚀防护性能，在所有ACET循环中|Z|约为10 Ω·cm即可体现。相比之下，当涂层厚度降至30 µm时，PPM共聚物的耐腐蚀性明显优于共混PPM，前者的|Z|保持在10 Ω·cm以上，而后者则低于10 Ω·cm。此外，结合在254 nm紫外光下对涂层表面的光学研究，对许多电化学关键特征的分析证实了PPM共聚物制成的涂层具有内在的自愈能力，这与参考样品（即共混PPM）不同。
