A new and highly adaptable way to make 3D structures in a wide range of different shapes has been reported in a new HOT article, published in Materials Horizons. The technique allows adjustment of both the shape transition process and the final shape at the same time.
The strategy, which Jian Ji’s group at Zhejiang University describe as a “writing” process, uses polymer nanosheets as blank “paper”. These are guided into making specific shape changes with a near infra-red laser beam “pen”. By controlling which shape changes happen at which time, several sheets can be woven together into a complex interlocking structure. Unlike previous techniques, the order of these changes can be easily altered to change the interlocking pattern.
Ji’s group used pre-stretched composite sheets of Nafion, a shape memory polymer, and polydopamine. When a NIR laser was applied to specific parts of the nanosheet, the polydopamine converted the light energy into heat. This caused internal stress between the heated and non-heated parts, triggering a shape transition of the sheet to relieve the stress. Changing the shape or intensity of the laser beam or where it was applied modulated the shape change, giving rise to a huge number of possible shapes.
Because the nanosheets don’t require special pretreatment before forming each particular shape, a variety of shapes can be made from the same starting material in quick succession. The technique could in future be used to make “personalised” components for the healthcare industry.
Read the full article here:
A ‘‘writing’’ strategy for shape transition with infinitely adjustable shaping sequences and in situ tunable 3D structures
Tingting Chen, Huan Li, Zuhong Li, Qiao Jin and Jian Ji
Mater. Horiz., 2016, DOI: 10.1039/C6MH00295A
Susannah May is a guest web writer for the RSC Journal blogs. She currently works in the Publishing Department of the Royal Society of Chemistry, and has a keen interest in biology and biomedicine, and the frontiers of their intersection with chemistry. She can be found on Twitter using @SusannahCIMay.