New paper reporting on Eco-friendly sol-gel derived sodium-based ormolytes, by UTAD-CRM. Fernandes, R. Leones, S. Pereira, A.M.S. Costa, J.F. Mano, M.M. Silva, E. Fortunato, V. de Zea Bermudez, R. Rego.
The sol-gel method was employed in the preparation of organic/inorganic biohybrid ormolytes composed of a di-urethane cross-linked poly(ε-caprolactone) (PCL(530))/siloxane matrix doped for the first time with different amounts of sodium triflate (NaCF3SO3.xH2O). The samples are semi-crystalline and thermally stable up to ca. 250 ºC. The maximum ionic conductivity (4.1 × 10-7, 1.5 × 10-4 and 8.8 × 10-4 S cm-1 at 30, 49 and 97 ºC, respectively) was attained at n’ = 6, where n’ (composition) corresponds to the number of (C(=O)(CH2)5O) repeat units of PCL(530) per sodium ion. Selected ormolytes were employed in the construction and characterization of prototype electrochromic devices (ECDs). Tests with ECDs incorporating poly(oxyethylene)/siloxane(U(600))nNaCF3SO3 (where n is the ratio of oxyethylene units per sodium ion) ormolytes already reported were also performed. The devices exhibited fast switching time of ca. 30 s. At 555 nm the ECD@U60063Na device exhibited the highest optical density value (Δ(OD) = 0.12) and coloration efficiency for bleaching (CEout 131 cm2 C-1, 50th cycle) and good optical memory. The ECD@PCL58Na device exhibited a CE value for coloration similar to that of ECD@U60063Na (CEin -116 cm2 C-1, 50th cycle) and a very good stability. However the Δ(OD) value for the latter device was much higher (0.12 versus 0.061)http://dx.doi.org/10.1016/j.electacta.2017.02.098