Researchers have used a three-dimensional (3D) printing technique to stack nanometre-scale polymer threads on top of one another, forming a tiny wall.

A promising 3D nanoscale printing method involves spinning nanofibres out of a liquid under a strong electrical field. But only certain shapes have been printed this way, because the fibres tend to electrically repel each other. To solve this problem, Minhee Lee and Ho-Young Kim of Seoul National University fired polymer nanofibres onto a metal template sitting on top of a grounding plate that quickly drains the deposited fibres of charge. The fibres then spontaneously attract each other, and stack to form a free-standing wall.

The technique cannot yet be used to print objects with sharp corners but could still be useful for building, for example, tiny transistors, the authors say.

Langmuir 30, 1210–1214 (2014)