A new study from researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), Princeton University, Lawrence Livermore National Laboratory, and Brookhaven National Laboratory has significantly advanced 3D printing of liquid crystal elastomers (LCEs), a class of synthetic soft materials that can change shape in response to heat. This breakthrough offers potential applications in areas such as soft robotics, prosthetics, and compression textiles.
By identifying effective methods to control the properties of LCEs during 3D printing, the researchers have laid out a systematic approach that allows for predictable and controllable alignment of these materials. Achieving this alignment was previously a challenging process involving much trial and error. The new research utilizes an X-ray characterization method to quantify mesogen alignment during printing at the microscale, forming a fundamental framework for optimizing the design and fabrication of LCEs.
The study found that manipulating printing parameters such as nozzle design, speed, and temperature enables the desired molecular-scale alignment, impacting the shape-morphing and mechanical behavior of the materials. Notably, the investigation involved varying nozzle shapes and flow dynamics to produce filaments with divergent alignment characteristics.
The results indicate that a hyperbolic nozzle shape produces more uniform alignment compared to traditional designs, which can help fabricate LCE structures with specific programmed behaviors. This work offers new insights into the processing-structure-property relationships of LCEs, aiming to enhance their functionality in future applications.
This research was funded by the National Science Foundation, the U.S. Army Research Office, and various resources from the Department of Energy. For detailed findings, the study is published in the Proceedings of the National Academy of Sciences and highlights the collaborative effort to innovate in the realm of advanced materials.