“…HCFs have shown excellent electron field emission characteristics [ 27 , 28 , 29 , 30 ] and wide band absorption of electromagnetic waves [ 31 , 32 , 33 , 34 , 35 ]. Because of their unique morphology and properties, HCFs have been proposed for potential applications in polymer additives [ 36 , 37 , 38 ], supercapacitor electrodes [ 39 , 40 ], catalysts [ 41 ], catalyst supports [ 42 , 43 ], hydrogen adsorption [ 39 , 44 , 45 ], generator or detector of magnetic field [ 46 ], an electrical inductors [ 21 ], micro/nanospring [ 47 ], sensors [ 21 , 48 , 49 ], nanodevices [ 50 ], etc .…”