Ion conducting and paramagnetic d-PCL(530)/siloxane-based biohybrids doped with Mn2+ ions

Amorphous poly(ε-caprolactone) (PCL(530))/siloxane ormolytes doped with manganese perchlorate (Mn(ClO4)2) (d-PCL(530)/siloxanenMn(ClO4)2 with n = 20, 50, and 100), thermally stable up to at least 200 °C, were synthesized by the sol-gel method. Ionic conductivity values up to 4.8 × 10−8 and 2.0 × 10−6 S cm−1 at about 25 and 100 °C, respectively, were obtained for n = 20. FT-IR data demonstrated that the hydrogen bonding interactions present in the non-doped d-PCL(530)/siloxane host hybrid matrix were significantly influenced by the inclusion of Mn(ClO4)2 which promoted the formation of more oxyethylene/urethane and urethane/urethane aggregates. In addition, the Mn2+ ions bonded to all the “free” CO groups of the urethane cross-links and to some of the “free” ester groups of the amorphous PCL(530) chains. In the electrolytes, the ClO4− ions were found “free” and bonded to the Mn2+ ions along a bidentate configuration. The magnitude of the electron paramagnetic resonance (EPR) hyperfine constant of the analyzed samples (A ≈ 90×10−4 cm−1) suggested that the bonding between Mn2+ ions and the surrounding ligands is moderately ionic. The synthetized d-PCL(530)/siloxanenMn(ClO4)2 biohybrids have potential application in paramagnetic, photoelectrochemical and electrochromic devices.