Figure 10.

(a) Schematic representation of a CuPT crystal encapsulated in silica aerogel matrix (not to scale). The aerogel encloses the CuPT crystal within a mesoporous silica shell, which allows the penetration of seawater while entrapping the solid CuPT crystal. (b) The working principle of the aerogel material in the coating matrix. (c) A cross-sectional view of an antifouling coating, containing CuPT-loaded aerogels, exposed to seawater. After dissolution of the soluble pigments, a porous leached layer forms. Only activated biocides can diffuse through the leached layer pores and give biocidal protection at the coating surface. Empty aerogels, present in the outermost surface layer, are polished away by the flow of seawater.