From Short Electrospun Nanofibers to Ultralight Aerogels with Tunable Pore Structure

Nanofiber production by electrospinning has made great progress over the past two decades. Recently the research area was revolutionized by a novel post-processing approach. By cutting the endless and intertwined nanofibers into short pieces, it is now possible to reassemble them into interconnected 3D structures. Such highly porous structures are built from dispersed short nanofibers by freeze-casting. This solid templating process controls the structures' ultimate properties and architecture in terms of primary and secondary pores below 5 ?m and between 10 and 300 ?m, respectively. The objective of this review is to provide insight into this young field of research, in particular highlighting the processing steps, materials and current applications, from scaffolds for tissue engineering, acoustics, sensors and catalyst supports to filtration.