Researchers from Harvard, Princeton, and Brookhaven National Lab have developed a new method to control the properties of liquid crystal elastomers (LCEs) during 3D printing. LCEs are shape-morphing materials that change shape in response to heat, similar to muscle contractions and relaxations. The team’s breakthrough allows them to print LCEs with predictable and controllable alignment of molecules, enabling the creation of materials with tailored properties. This is achieved by using an X-ray characterization method to visualize molecular alignment during the printing process.
The researchers identified that the shape of the 3D printer nozzle and flow conditions affect the alignment of liquid crystalline chains, which ultimately determines the material’s properties. By tuning nozzle design, printing speed, and temperature, the team can induce specific molecular alignment, leading to prescribed shape-morphing and mechanical behavior at the macroscale. The work opens up new avenues for creating LCE structures with programmed shape morphing and mechanics, such as adaptive structures and artificial muscles. The development of this playbook for printing LCEs paves the way for a range of applications in soft robotics, prosthetics, and compression textiles.