Facile Fabrication of Raspberry-like Composite Nanoparticles and Their Application as Building Blocks for Constructing Superhydrophilic Coatings

Monodisperse raspberry-like polystyrene@silica composite nanoparticles (RCNs) were readily prepared by a single-step sol-gel method, using oxygen plasma-treated monodisperse polystyrene (PS) spheres as cores. The fabricated composite particles have a well-defined structure and a surface morphology of dual-size roughness. The diameter of silica nanoparticles and their coverage degree on the surface of PS spheres could be easily tailored by adjusting the tetraethoxysilane concentration. Subsequently, porous silica hollow sphere coatings were fabricated by depositing the RCNs on polyelectrolyte-modified glass substrates via layer-by-layer assembly followed by calcination. Such porous silica hollow sphere coatings present unique superhydrophilic and antifogging properties even though the coverage degree of porous silica hollow spheres on substrates is only ca. 50%. Therefore, the obtained raspberry-like composite spheres are ideal building blocks for constructing superhydrophilic and superhydrophobic coatings.