Magnetically aligned carbon nanotubes in nanopaper for electro-activated shape-memory nanocomposites

A nanopaper that exhibits excellent electrical and electromagnetic performance is fabricated by incorporating magnetically aligned carbon nanotubes (CNTs) into carbon nanofiber (CNF) nanopaper. The morphology and structure of the aligned CNTs in nanopaper are characterized with scanning electronic microscopy (SEM). A continuous and compact network observed from the microscopic images indicates that the nanopaper enabled shape-memory polymer (SMP) nanocomposites could have excellent electrically conductive properties. Electromagnetic CNTs were blended with and, aligned into the nanopaper upon a magnetic field, significantly lower the electrical resistivity of SMP nanocomposites. This experimental results reported here suggested that the average electrical resistivity decreased from 5.3 to 2.0 Ω·cm as the weight of magnetic CNTs alignment into the nanopaper increased from 10 to 50 wt.%. Finally, shape recovery actuation of 1.8 g nanopaper enabled SMP nanocomposite induced by electrically resistive heating was achieved in 119 s under a 70 mA electric current.