Nanostructured Silicon Containing Materials Derived from Solid State Pyrolysis of Sililated Polyphosphazene Derivatives

Abstract

Pyrolysis of the silicon-containing polymer {(NP[O2C12H8])0.5[NP(OC6H4·SiMe3)2]0.5−x [NP(OC6H5)·(OC6H4SiMe3)]x}n (1) (x = 0.13), (2) (x = 0.3), and (3) {(NP[O2C12H8])0.5[NP(OC6H4SiMe2Ph)2]0.2·[NP(OC6H5)(OC6H4SiMe2Ph)]0.3}n in air at 600 °C, 800 °C and 1000 °C results in the formation of nanostructured SiP2O7, along with P4O7. The morphology as well as the size and shape of the nanostructures is observed to depend on both the mole fraction of silicon, the polymer precursor and the temperature of the pyrolysis. The first observation of nanotube formation using polyphosphazenes as a template, was noted during pyrolysis of the precursor (1) at 600 °C. The surface morphology of the Si or SiO2, studied by AFM, depends strongly on the crystallinity of the wafer surface used during deposition. Regular lance or point-like structures were obtained from SiP2O7 deposited on SiO2 from its precursor (2). The unique formation of micro and nanostructured SiP2O7 is discussed and a mechanism of the formation of the nanostructured materials is proposed.