A novel double-decker structural fluorinated POSS and a diphenol POSS were first synthesized for preparing a unique “cage–cage”-shaped hydrophobic fluoropolymer film with a low dielectric constant.

A series of poly(arylene ether)s were synthesized with a diphenol POSS (2OH-DDSQ) and perfluoro-aromatics including decafluorobiphenyl, decaflurobenzophenone and decafluorodiphenyl sulfone via a two-step nucleophilic aromatic substitution polymerization. The chemical structures of the polymers were confirmed by ¹⁹F-NMR and ¹H-NMR. All the polymers exhibit not only low dielectric constants in the range of 1.85–2.37 at 1 MHz at room temperature but also low dielectric losses, hydrophobic properties, low water uptake and good thermal properties. In particular, the DDSQ-DFPK film showed the ultra-low dielectric constant of 1.83 at 1 MHz. With increasing polarity of the perfluoro-aromatics, the water contact angles decrease from 108° to 102°.

The prepared composites combine outstanding thermal conductivity and excellent electromagnetic interference shielding performance.