Novel strategy for tailoring of SiO₂ and TiO₂ nanoparticle surfaces with poly(ε-caprolactone)

A novel strategy was developed for tailoring of SiO₂ and TiO₂ nanoparticle surfaces with poly(ε-caprolactone) (PCL). Thus, a self-curable polyester, poly(2-hydroxypropylene maleate) was adsorbed on the nanoparticle surfaces and heated to 180∈°C to give a cross-linked polyester layer with residual hydroxyalkyl groups on their surfaces. Surface-initiated polymerization of ε-caprolactone from hydroxyalkyl groups on the surfaces yielded core-shell nanoparticles with cross-linked core and PCL shells (22.2-71.4%). The organic shell layers around the nanoparticle cores were evidenced by transmission electron microscopy, dynamic light scattering, and thermogravimetric analyses techniques. The core-shell nanoparticles were then employed in preparing the stable and the homogenous dispersions with poly(methyl methacrylate-stat-butyl acrylate) solutions. An application of the solutions onto glass substrates yielded uniform and nearly transparent free standing films (40-60 μm) with good homogeneity as inferred from scanning electron microscopy pictures.