Adv. Mater. http://doi.org/gcqsvn (2017)

By using a highly uniform distribution of functionalized carbon nanotubes (CNTs) in a polydimethylsiloxane (PDMS) matrix, Zhongjie Huang and co-workers have made a two-dimensional array of photoactuated pens with an actuation efficiency of 200 nm mW−1. Their pen arrays were fabricated by curing the moulded composite paste on a silicon wafer that contained an array of microfabricated pyramidal holes. The pitch and base length of the pyramidal holes are 60 μm and 20 μm, respectively. A pyramidal pen can locally expand on light irradiation with a focal spot of 2 mm in radius and an average light intensity of 100 mW cm–2. On irradiation, the local deformation moves the pen out of plane into contact with a substrate so that local material transfer occurs. This actuation occurs locally, meaning pens outside the illumination area do not print. The selected pen can move more than 3 μm out of plane, enabling controllable and high-quality printing.

Credit: Wiley