Growth of Polyglycidol in Porous TiO₂ Nanoparticle Networks via Initiated Chemical Vapor Deposition: Probing Polymer Confinement Under High Nanoparticle Loading

Initiated chemical vapor deposition (iCVD) enables the uniform growth of polyglycidol (PGL) within mesoporous layers of TiO₂ nanoparticle networks. Through the cationic ring opening polymerization of glycidol, conformal deposition of PGL by iCVD results in up to 91% of the available pore space being filled. This yields polymer nanocomposites with high nanoparticle loading of 82 wt% and 54 vol%. The glass transition of the PGL nanocomposite is found to increase significantly by 50 °C–60 °C compared to the bulk PGL polymer. This marked temperature rise has been attributed to significant hydrogen bonding interaction of the oxygen and hydroxyl groups in the polymer with the hydroxyl groups on the surface of the TiO₂ nanoparticles. Such interactions under polymer confinement are only possible as a result of the tight integration of the polymer and inorganic materials afforded by the iCVD approach.