Assembly route toward raspberry-like composite particles and their controlled surface wettability through varied dual-size binary roughness

•Sulfonated PS template/aniline medium method was used.•Optimal sulfonation condition was obtained.•Got composite particles of varied dual-size binary morphology.•Wettability of varied dual-size roughness surface was studied. Sulfonated PS template/aniline medium method was used to assemble raspberry-like composite particles with varied dual-size binary morphology. The assembly efficiency of SiO2 particles on templates was found to increase with sulfonation temperature as well as sulfuric acid concentration. For sulfonation time one turning point appeared because there existed one balance between microgel structure formation and PSS chains detachment. The optimal preparation condition was finally obtained and proved effective for other types of anionic particles. Wettability of surfaces with varied binary roughness was studied and the results showed that dual-size structure could further improve the hydrophobic performance. The contact angles were found to increase with the size ratio of template particles/outer particles.