New hybrid silsesquioxane materials with sterically hindered carbosilane side groups

Unique silsesquioxane materials, bearing highly sterically hindered carbosilane substituents at SiO3/2 centre, were derived from a novel precursor – (Me3Si)3CSiMe2CH2CH2Si(OEt)3 – in a hydrolytic condensation process under nucleophilic catalysis conditions. As proved by analytical results, crystalline or ladder-like [(Me3Si)3CSiMe2CH2CH2SiO3/2]n (PTSiSS) were obtained, depending on the applied reaction conditions. Due to the intrinsic features of (Me3Si)3CSiMe2–carbosilane substituent (the bulk and large amount of Si–C bonds), the obtained ladder-like silsesquioxanes show specific properties (good solubility, low dielectric constant κ).