Self-assembly behavior of hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane-capped poly(ɛ-caprolactone) in epoxy resin: Nanostructures and surface properties

The organic–inorganic amphiphile, hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS)-capped poly(ɛ-caprolactone) (POSS-capped PCL) was synthesized via the ring-opening reaction of ɛ-caprolactone, which was initiated by 3-hydroxypropylhepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS) with stannous (II) octanoate [Sn(Oct)2] as the catalyst. The organic–inorganic nanocomposites were prepared via the in situ polymerization of epoxy monomers in the presence of the POSS-capped PCL. The atomic force microscopy (AFM) shows that the organic–inorganic hybrids possess the nanostructures. In view of the miscibility of the sub-components of the organic–inorganic amphiphile [i.e., PCL chains and POSS cages] with epoxy after and before curing reaction, the formation of the nanostructures in the thermosets followed the mechanism of self-assembly. The surface properties of the organic–inorganic nanocomposites were investigated by means of static contact angle measurements and X-ray photoelectronic spectroscopy (XPS). It is demonstrated that the improvement in surface hydrophobicity was ascribed to the enrichment of the POSS cages on the surface of the materials.