Figure 4.

Morphology of electrospun nanofibers a columnar nanofibers [90] b beaded nanofibers [91] c porous nanofibers [92] d grooved nanofibers [93] e nanobelt nanofibers [95] f nanograin nanofibers [94].

Reproduced with permission from reference [90]. Copyright 2019, Elsevier B.V. Reproduced with permission from reference [91]. Copyright 2012, Elsevier B.V. Reproduced with permission from reference [92]. Copyright 2015, Elsevier Ltd. Reproduced with permission from reference [93]. Copyright 2016, Elsevier B.V. Reproduced with permission from reference [94]. Copyright 2013, Elsevier B.V. Reproduced with permission from reference [95]. Copyright 2011, Elsevier Ltd