A team at Harvard University has developed a rotational 3D printing method to create filaments that change shape on demand when exposed to heat.
Shape-Shifting Filaments: A New Frontier in 3D Printing
Summary
Scientists have engineered filaments from two distinct materials: an active liquid crystal elastomer (LCE) and a passive elastomer. When heated above a specific transition temperature, the LCE contracts along a molecularly aligned axis, causing the filament to bend, twist, contract, or expand. The passive elastomer provides the necessary structural support and guides the resulting movement.
The key innovation lies in the printing process: It extrudes both materials side-by-side through a rotating nozzle, embedding a helical molecular alignment that directly encodes the desired curvature and twist—without requiring any post-processing.
Research Details and Publication
- Leadership: The research was led by Jennifer Lewis.
- Publication: Published in the Proceedings of the National Academy of Sciences on April 22, 2026 (DOI: 10.1073/pnas.2537250123).
- Collaborators: The study was conducted in collaboration with L. Mahadevan and Joanna Aizenberg.
- Funding: The work received support from the National Science Foundation and the ARO MURI program.
Demonstrated Applications
The team showcased several functional prototypes:
- Sinusoidal filament structures that can expand, straighten, contract, or shrink, depending on the placement of the active LCE.
- Flat lattices that function as thermally responsive filters, altering their porosity to selectively allow or trap particles when heated or cooled.
- Free-standing lattice "grippers" that can clasp, lift, and release rod-like objects in response to temperature changes.
- A lattice that morphed into a dome shape when heated in an oil bath, closely matching computational simulations.
Technical Specifications
The filaments have been printed with a diameter as small as approximately one-tenth of a millimeter. Researchers suggest further miniaturization is possible.
Future Directions
Future versions of the technology may incorporate embedded liquid metal channels for electrical actuation or integrated sensing capabilities. Potential applications outlined by the researchers include soft robotics, biomedical devices, and adaptive filters.