Yang Lei,Yongjing Liu,Qiang Liu,Zhengbin Xu,Bo You,Xiaoliang Mo,Limin Wu,Heng Man,Wenxia Ma,Haitao Wang
The service life of metal and other infrastructure requires extending through eco-friendly, low-carbon technology. Here, a nacre-mimetic γ-Fe2O3/reduced graphene oxide (FrGO)/zinc-containing epoxy coating (FrGO/Zn/epoxy coating) was fabricated by spraying a mixture of waterborne epoxy resin, zinc flakes, and magnetic conductive FrGO under a magnetic field. The FrGO, which was synthesized by in situ redox and precipitation, was aligned in the zinc-containing coatings (ZCC), and it oriented the zinc flakes in the direction of the magnetic field to mimic the lamellar structure of nacre. The obtained anti-corrosion coating showed enhanced barrier protection and cathodic protection, which was confirmed by the electrochemical tests and salt spray test results. The waterborne coatings less than 50 μm thick with parallelly aligned FrGO and 30 wt % zinc flakes exhibited a long cathodic period lasting more than 99 days and excellent barrier performance with a high initial coating resistance of 5.31 × 109 Ω·cm2, which was superior to that of the conventional zinc-rich coating containing 80 wt % zinc (80 days, 3.74 × 103 Ω·cm2). The dual anti-corrosion mechanism of the waterborne FrGO/Zn/epoxy coating was investigated. The integrity and long-term cathodic protection of the coatings were derived from the compactness achieved by the nacre-mimetic structure and the interface chemical and hydrogen bonding crosslinking interactions and the high, uniform zinc utilization achieved by the aligned FrGO-Zn charge transmission network. This work provides a feasible nacre-inspired strategy to fabricate a lightweight anti-corrosion waterborne ZCC that is resource-efficient and promising in creating compact materials with other functional properties, such as electromagnetic shielding and conductive networks.
Yang Cao,Luo Jialiang,Wang Yue,Xue Yiqing,Liu Guigao,Lu Zhehong,Wang Suwei,Jiang Wei
Rational microstructure design and compositional regulation have emerged as effective pathways to enhance electromagnetic wave (EMW) absorption, However, simultaneously achieving strong absorption, broad bandwidth, thin thickness and low filler loading remains challenging. Herein, three-dimensional hierarchical heterostructures comprising amorphous carbon-wrapped magnetite supported on flower-like reduced graphene oxide (Fe₃O₄@C/FRGO) was constructed through spray-drying assembly, spatially confined solvothermal crystallization, and defect-modulated carbonization. By tailoring the reduction degree of FRGO and tuning ferrite composition through thermal treatment, the dielectric-magnetic properties and interfacial interactions are precisely regulated. With merely ≈ 3.26 wt% incorporation of FRGO, the optimized composite exhibits a minimum reflection loss (RL min ) of -66.29 dB at 1.94 mm (20 wt% filler) and a broad effective absorption bandwidth (EAB) of 6.60 GHz (11.30–17.90 GHz) at 2.73 mm (30 wt% filler). This exceptional performance is attributed to the engineered heterointerfaces that facilitate multi-path energy dissipation via magneto–dielectric coupling optimized impedance matching, intensive interfacial polarization from abundant hierarchical architectures and the flower-like structure induced multiple scatterings. This study highlights the pivotal role of interfacial engineering in heterostructured absorbers and offers a design paradigm for high-performance EMW-absorbing materials through coordinated component–structure modulation. Graphical abstract The alternative text for this image may have been generated using AI.
Hydrophobic and dispersible functionalized reduced graphene oxide (FrGO) was employed to prepare chitosan gel droplets by crosslinking an inverse Pickering emulsion. The emulsion was prepared using toluene as the continuous phase and a chitosan aqueous solution as the dispersed phase. The effects of the FrGO concentration and the water/oil ratio on the chitosan droplet morphology were studied. At appropriate concentrations, the FrGO acted as a stabilizer and chitosan gel droplets were formed. Decreasing the FrGO concentration or increasing the water/oil ratio was unfavorable to the formation of chitosan droplets. Using this method, drug loaded chitosan gel droplets (microgels) were prepared and their release profiles as well as the factors that influence the drug release were investigated.
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