Poly(cyclooctadiene-co-Ionic Liquid) Networks Cross-Linked via POSS–POSS Interactions

Abstract

Organic–inorganic terpolymers comprising cyclooctadiene, ionic liquid, and polyhedral oligomeric silsesquioxanes (POSS) were synthesized through ring-opening metathesis polymerization, the POSS cages serving as the structural units of main chains. The self-assembled morphologies were created in the organic–inorganic terpolymers; the POSS cages were aggregated into microdomains of 20–30 nm. The generation of POSS microdomains led to the physical cross-linking with the POSS microdomains as the netpoints. The physical cross-linking was robust and thermally stable, endowing the terpolymers with improved mechanical strengths. Furthermore, the terpolymers displayed excellent self-adaptivity against stretching; the elongation at break can be as high as ε_b = 952.7%. In the meantime, the physical cross-linking endowed the terpolymers with shape memory properties. Benefiting from the intense exchange of ionic bonds, the organic–inorganic terpolymers were self-healable (or reprocessable). Also, the exchange of ionic bonds imparted reconfigurability to the shape memory terpolymers. With the ionic liquid moieties as the charge carriers, the organic–inorganic terpolymers can serve as the solid polyelectrolytes, and the ionic conductivity of which can be as high as 1.52 × 10^–5 S × cm^–1 at 300 K.