Performance improvement of continuous carbon nanotube fibers by acid treatment

Zhang Qiang^{1, 3}, Li Kewei¹, Fan Qingxia^{1, 3}, Xia Xiaogang^{1, 3}, Zhang Nan¹, Xiao Zhuojian^{1, 3}, Zhou Wenbin¹, Yang Feng^{1, 3}, Wang Yanchun^{1, 2, 3}, Liu Huaping^{1, 2, 3}, Zhou Weiya^{1, 2, 3, †}

(color online) (a) and (b) SEM images of the surface and fracture morphology of a CNT fiber. (c) SEM image of a continuous reticulate network of CNT bundles with Y-type junctions indicated by dot circles. The inset shows an HRTEM image of CNTs with dominant single-walled structure. (d) Raman spectrum for the fiber with the excited laser wavelength of 633 nm. The inset shows RBM peaks located between 130 cm⁻¹ and 270 cm⁻¹.