Low temperature plasma enhanced growth of carbon nanostructures on quartz fibres

This work investigates the growth of carbon nanostructures (CNSs) on quartz fibres through chemical vapour deposition (CVD). As the high temperatures (600-1000 °C) required in traditional thermal CVD are known to degrade the tensile strength of quartz fibres, a plasma enhanced chemical vapour deposition (PECVD) technology is here proposed to achieve low temperature (≤ 550 °C) growth of CNSs. Both a thermal CVD and a PECVD process are performed on quartz fibres at temperatures of 640 °C and 540 °C, respectively. As opposed to the 74% fibre strength loss resulting from the thermal CVD process, only a 13% strength loss is measured after the PECVD process through single fibre tensile test, confirming the effectiveness of this strategy in preserving the fibre mechanical response. Scanning electron microscopy is employed to characterize the surface morphology of quartz fibres after catalyst precursor deposition, hydrogen annealing pre-treatment and CNS growth for both processes. CNS morphologies are compared in terms of CNS length, orientation, and spatial arrangement and the effect of plasma and catalyst morphology is addressed.