Coupling photoluminesce and ionic conduction properties trough the different coordination site of siloxane-polyether hybrid material

In this paper we demonstrate that each functional group of ureasil organic-inorganic hybrid (OIH) material can serve as specific coordination site of a given active host specie allowing the possibility to couple different... [ view full abstract ]

In this paper we demonstrate that each functional group of ureasil organic-inorganic hybrid (OIH) material can serve as specific coordination site of a given active host specie allowing the possibility to couple different functional properties. To demonstrate this concept we use the sol-gel process to produces di-urea cross-linked siloxane-polyethylene oxide (U-PEO) and polypropylene oxide (U-PPO) hybrid host framework of similar molecular weight (1900 g.mol^-1 and 2000 g.mol^-1 for PEO and PPO) with lithium triflate and europium chloride salts as active guest species of ionic conduction and photoluminescence properties, respectively. The comparison of IRFT spectra and small angle X-ray scattering (SAXS) results of both the single and the double salt loaded U-PEO and U-PPO host evidence in all case the specificity of coordination of Eu³⁺ by the carbonyl group of the urea bridge and of Li⁺ by the ether type oxygen of PEO and PPO chains. The PL results evidence that the Li⁺ loading does not interfere with the luminescent properties of the Eu³⁺ loaded OIH. Although the Eu³⁺ loading cause a small interference on the ionic transport, the co-loading with Li⁺ grants the macroscopic ionic conduction of the transparent and luminescent hybrid material. Due to the hydrophobicity of U-PPO and the hydrophilicity of the U-PEO the former has the best PL property while the later presents the higher ionic conduction. The obtained results suggest that a combination of both properties in a transparent elastomeric material could be useful for the development of electro-luminescent devices.