Camphene effect for morphological change of electrospun SnO₂ nanofibres: From dense to fibre-in-hollow and to hollow nanostructures

We fabricated various morphological SnO₂ nanofibres (NFs), which are controlled from dense to fibre-in-hollow and hollow nanostructures, by electrospinning with the introduction of camphene. To control the morphologies of the SnO₂ NFs, the relative loading amounts of camphene to solvent were adjusted to be 0, 50, and 125 wt%. As a result, the SnO₂ NFs formed at 0 wt% camphene showed a dense nanostructure due to the shrinkage effect caused by the thermal decomposition of the polyvinylpyrrolidones. For 50 wt% camphene, the SnO₂ NFs formed the fibre-in-hollow nanostructure because of the occurrence of the Kirkendal effect on the surface of the as-spun SnO₂ NFs. For 125 wt% camphene, the morphology exhibited a hollow nanostructure because of the occurrence of the Kirkendal effect on the entire area of the as-spun SnO₂ NFs. Thus, as the loading amount of camphene was increased, the morphology of the SnO₂ NFs changed from dense to fibre-in-hollow and to hollow.