Homo- and co-polymers of cage silsesquioxane-tethered methacrylate and styryl monomers: effects of linker length and rigidity on film transparency

Abstract Polymers containing polyhedral oligomeric silsesquioxane (POSS) side chains often crystallize, preventing transparent film formation. To clarify the influence of linker structure on POSS packing, herein, we synthesized two homopolymers bearing propyl methacrylate (P1) or styryl (P2) POSS monomers, as well as their copolymer (P3). P1 and P3 formed transparent films, whereas P2 produced brittle, cracked films, despite its amorphous nature. POSS crystallization was suppressed in P1–P3, in contrast with a control polymer containing a long alkyl linker. We demonstrate that linker rigidity and copolymer architecture are key parameters for designing transparent and thermally robust POSS-based hybrid polymers.