A controlled release strategy of antifouling agent in coating based on intercalated layered double hydroxides

• A controlled release method of antifouling agent was presented based on paeonolsilate (PAS) intercalated into Zn2Al-LDH.
• The model coating with Zn2Al-PAS-LDH composite was prepared.
• The controlled release performance of the Zn2Al-PAS-LDH coating was studied by UV–vis spectra.
• The antifouling performance of the coating was verified using the adhesion experiment of Ulva zoospores.

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.