Design of novel RGO/2D strip-like ZIF-8/DMAOP ternary hybrid structure towards high-efficiency microwave absorption, active and passive anti-corrosion, and synergistic antibacterial performance

In order to meet the requirements of the marine environment for microwave absorption (MA) materials, we put forward the strategy of constructing multi-functional composite materials, which integrate microwave absorption, anti-corrosion, and antibacterial properties. Herein, graphene oxide (GO) was used as a template to induce the growth of zeolitic imidazolate framework-8 (ZIF-8), simultaneously as a two-dimensional (2D) nanocontainers to load corrosion inhibitors to achieve pH-responsive and self-healing properties. Finally, quaternary ammonium salt (dimethyl octadecyl(3-trimethoxylsilyl propyl) ammonium chloride (DMAOP)) and sodium ascorbate (VCNa) were introduced to achieve synergistic antibacterial activity and the reduction of GO. The 2D strip-like structure of ZIF-8 was due to the confined growth induced by the electrostatic attraction between ZIF-8 and GO sheets. The as-obtained reduced GO (RGO)/ZIF-8/DMAOP₅ exhibited excellent microwave absorption (MA) properties, with a minimum reflection loss (RL) value of −47.08 dB at 12.73 GHz when the thickness was 2.8 mm. Moreover, the effective absorption bandwidth reached 6.84 GHz. After soaking in 3.5% NaCl solution for 35 days, the RGO/ZIF-8/DMAOP₅-0.7% coating still achieved an impedance value of 4.585 × 10⁷ Ω·cm² and a protective efficiency of 99.994%, providing superior anti-corrosion properties. In addition, fantastic antibacterial activity was obtained, with the antibacterial rates of RGO/ZIF-8/DMAOP₁₀ reaching 99.39% and 100% against Escherichia coli and Staphylococcus aureus. This work could open new avenues towards the development of a new generation of multifunctional MA materials.