Design and architecture of low-dielectric-constant organic–inorganic hybrids from octahydridosilsesquioxanes

Molecular design and architecture of four novel organic–inorganic network hybrids were implemented via hydrosilylative addition reaction of octahydridosilsesquioxanes (H8-POSS) with dienes. The structural characterization by the FTIR, 13C MAS NMR and 29Si MAS NMR technologies, respectively, indicates that two monomers are chemically bound to each other to form three-dimensional network hybrids that possess well film-formability. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that no phase separation occurred in the hybrid films, implying that the POSS molecules are uniformly dispersed into the polymeric system at the nanoscale. All POSS-containing well-dispersed hybrid films exhibit a good thermal stability with a decomposition temperature higher than 350 °C, and enhanced mechanical properties of a hardness of 0.21–0.26 GPa and the elastic modulus of 7.67–8.85 GPa, and low dielectric properties with a dielectric constant of 2.43–2.78. Interestingly, these properties can be further tuned by adjusting the length and the structure of the linking chain between POSS cages.