Ultrasonication induced adsorption of carbon nanotubes onto electrospun nanofibers with improved thermal and electrical performances

Abstract

Ultrasonication was employed to induce the uniform adsorption of carbon nanotubes (CNTs) onto electrospun polymer nanofiber (EPNF) surfaces. Compared with pristine CNTs, acid treated CNTs became shorter, which facilitated their decoration onto the EPNF surfaces more tightly and densely. Under ultrasonication, CNTs possessing strong energy hit the EPNF drastically, leading to the partial softening of the EPNF at the impact sites, and then the CNTs could be successfully embedded into the EPNF surface. Our study demonstrated that CNT adsorption could not be achieved by the direct immersion of the EPNF into the CNT solution, even at elevated temperatures. It was also found that the existence of surfactant in the solution could prevent the CNTs adsorbing onto the fiber surface, which suggested that it was really a surfactant-free method. After CNT adsorption, the temperature for the maximum weight loss rate of the polyurethane (PU) nanofibers increased from 360.7 °C to 397.7 °C, which was attributed to the uniform dispersion of CNTs as well as the strong interaction between the CNTs and the polymer nanofibers. The conductivity was also significantly raised to 10 S m⁻¹, derived from the formation of a conductive percolation network. Furthermore, porous nanofiber-like CNT cages could be obtained after the removal of the polymer component by pyrolysis. This approach provides a new avenue for harvesting CNT decorated nanofiber composites with improved performances.