Growth of carbon nanofibers/tubes by an in-situ polymerization route without metal-catalyst

An in-situ pyrolytic and polymerizable method was investigated to grow carbon nano-fibers/tubes (CNF/CNT) without metal-catalysts. The 3 mol % yttria-stabilized zirconia hollow fiber membranes (3YSZ-HFM) were used as supports for growing the CNF/CNT. The polyethersulfone (PES) and polyvinylpyrrolidone (PVP) were used as polymer binders and carbon sources. The as-grown CNF (formed at 1250 °C/4h) had diameters of 50-100 nm and lengths of 1-50 μm, and the length gradually decreased along radial direction of the supports. The as-grown CNT (formed at 1450 °C/4h) were shorter and larger in diameter. A novel solid-state transformation mechanism was proposed, in which the carbon black particles (CB) were the carbonized products of PES/PVP, then the CB grew into the CNF/CNT. Thermal stresses originated from sintering of CB itself and 3YSZ particles were believed to be the driving forces that promoting the CNT/CNF nucleation and growth. The thermal stresses of the pure 3YSZ-HFM and 3YSZ/(CNF/CNT)-HFM were theoretically and experimentally discussed base on linear elastic thoery and Raman spectroscopy.