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A controlled release method of antifouling agent was demonstrated via the model coating which was fabricated by sodium paeonolsilate (PAS) intercalated into Zn2Al Layered Double hydroxides (LDH) and then dispersed in the mixture of acrylic resin and colophony with weight ratio of 2:1. The powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) confirm the intercalation of PAS into the galleries of Zn2Al-LDH. Some larger particles of Zn2Al-PAS-LDH composite in the coating were observed owing to its aggregation, which was revealed by Laser scanning confocal microscope (LSCM). The release tests of the Zn2Al-PAS-LDH coating in 3.5% NaCl solution showed that no burst release phenomenon occurred at the beginning stage and a slower release rate of PAS (0.54 ppm/d) was obtained compared with the pristine PAS coating (1.06 ppm/d), exhibiting its preferable controlled release behavior. The adhesion experiment using Ulva zoospores indicated that Zn2Al-PAS-LDH composite obviously increases the utilization rate of PAS owing to its controlling release property. Therefore, the present work provided a useful strategy to decrease the waste of antifouling agent and prolong the lifetime of antifouling coatings.

A hierarchical Mg/Ni/Al layered double hydroxide (LDH) framework has been fabricated via the in situ crystallization process on aluminum foam (denoted as Mg/Ni/Al LDH/Al-foam). XRD and SEM confirm that the as-prepared Mg/Ni/Al LDH displays flowerlike microspheres (2–5 μm) composed of numerous LDH nanoplatelets (1–2 μm in width and ~50 nm in thickness). The BET analysis shows that the specific surface area of the Mg/Ni/Al LDH is 96.8 m²/g owing to its hierarchical structure, which is much higher than that of the traditional bi-metal Mg/Al LDH. Two steps of the synthesis strategy were carried out in order to eliminate the competitive difference between cations composed of LDH. The present work provided a new strategy for a scale-up synthesis of well-crystallized tri-metal LDH materials on metal substrate by the in situ crystallization technique.