Eco-friendly sol-gel derived sodium-based ormolytes for electrochromic devices. (1st April 2017) - Fernandes, M.
Graphical abstract: Highlights: Two series of ormolytes doped with NaCF3 SO3 were prepared by the sol-gel route. The samples are thermally stable up to ca. 250 °C. Best room temperature conductivity was attained with a poly(ε-caprolactone)/siloxane network. An ECD with a POE/siloxane-based ormolyte produced a coloration efficiency of −116 cm 2 C −1 at 555 nm. Abstract: 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 (NaCF3 SO3 .xH2 O). The samples are semi-crystalline and thermally stable up to ca. 250 °C. 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 °C, respectively) was attained at n' = 6, where n' (composition) corresponds to the number of ester (C(O)(CH2 )5 O) 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))n NaCF3 SO3 (where n is the ratio of ether (OCH2 CH2 ) repeat units per sodium ion) ormolytes already reported were also performed. The devices exhibited fast switching time of ca. 30 s. At 555 nm theECD@U60063 Na device exhibited the highest optical density value (Δ(OD) = 0.12) and coloration efficiency for bleaching (CEout 131 cm 2 C −1, 50 th cycle) and good optical memory. TheECD@PCL58 Na device exhibited a CE value for coloration (0.12 versus 0.061) similar to that ofECD@U60063 Na (CEin −116 cm 2 C −1, 50 th cycle) and a very good stability. However the Δ(OD) value for the latter device was much higher.