Haoming Wei1,2, Yang Wei1 (), Yang Wu1, Liang Liu1, Shoushan Fan1,2, and Kaili Jiang1 ()
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1 Department of Physics & Tsinghua–Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China 2 Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Spinning carbon nanotube (CNT) yarns from super-aligned carbon nanotube (SACNT) arrays is a promising approach to fabricate high-strength fibers. However the reported tensile strengths of the as-prepared fibers are far below that of an individual CNT. It is therefore still a challenge to improve their mechanical strengths. Here we report that the tensile strengths and Young’s moduli can be further improved to 2.2 GPa and 200 GPa respectively, if we first treat the SACNT array with oxygen plasma by using a reactive ion etching (RIE) facility, then dry spin yarns from it and make composite fibers with polyvinyl alcohol. According to the experimental results obtained using scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), the improvement is attributed to the oxygen RIE process, as it can create functional groups on the outer walls of CNTs and thus improve the interaction between the CNTs and the polymer molecules.