Synthesis, gelation behaviour and evolution of oligomeric structure of BaTi double alkoxide

Abstract

BaTi (BT) double alkoxides were synthesized by refluxing Ba and Ti methoxyethoxides. The gelation behaviours of the mixed alkoxides and BT double alkoxide, and the evolution of BT double alkoxide structure were investigated. A remarkable increment in gelation time was found for the synthesized double alkoxide system, compared with the mixed Ba and Ti alkoxide. In the case of the double alkoxides it was also observed that the gelation time was greatly influenced by the refluxing time used during their synthesis. A shortest gelation time was observed in the double alkoxides for refluxing times in the range of 2–3 h, attributed to the evolution of their oligomeric structure during the refluxing period. The evolution can be suggested as a transition between non-crystalline and crystalline states, with the shortest gelation time being observed near the crystalline state. The application of BT double alkoxides as precursors enabled a higher degree of homogeneity to be achieved during the sol–gel transition, and the obtaining of the BaTiO 3 crystalline phase at lower temperatures (from 600°C), compared with the mixed alkoxides (750°C).