An interdisciplinary research team from the United States has developed a novel 3D printing process for fabricating cholesteric liquid crystal elastomers (CLCEs)—materials capable of changing color under mechanical stress. The team employed a coaxial direct ink writing (DIW) technique, which enables the printing of multilayered, mechanically stable structures with precise color control. The results were recently published in the journal Advanced Materials.
CLCEs belong to a class of soft, elastic materials with an ordered molecular structure that selectively reflects light. By altering this structure—through stretching or pressure—color changes can be induced, making CLCEs highly attractive for applications in active sensing, soft robotics, and adaptive surfaces. The researchers combined the color-changing elastomer with a transparent silicone shell, which serves as a support structure for coaxial extrusion.
“We wanted to bring the work [into the Lab] to have a mechanically or strain-stimulated material, where the color change can be used for remote detection,” LLNL engineer Caitlyn Cook Krikorian explained. “Once we found a viable material, we spent considerable time fine-tuning the DIW conditions, particularly shear rates, to maintain vibrant colors while also ensuring print fidelity to construct these bistable dome structures. In this paper we demonstrated we could print these structures, but this is just the tip of the iceberg as far as achievable print architectures.”
The printing process required precise control of shear conditions to ensure both structural accuracy and color intensity. The goal was to create so-called bistable dome structures that can reversibly deform under stress while providing visual feedback.
LLNL’s Katherine Riley highlighted that multi-stability has been used to create “robotic grippers that can snap open and closed, metamaterial sheets that can passively sense and record mechanical loads, and mechanical logic systems that can compute without conventional electronics.”
“When arranged into 2D or 3D metamaterial arrays, this architecture could be used for passive displays, and for sensors that display different colors to indicate different levels of mechanical loading have been applied,” Riley said.
Looking ahead, the team plans to further develop the printing architecture and integrate CLCE-based materials as sensitive structures directly into functional components. Next steps will investigate how the materials’ mechanical properties adapt to changing loads and whether these responses can be permanently recorded. The project is supported by a strategic funding program at LLNL aimed at the development of so-called “sentient materials”—materials that not only respond to external stimuli but can also be purposefully tuned and adapted.
Metal Binder Jetting: The Key to Efficient Tool Manufacturing? - Exclusive Insights from INDO-MIM
Fill out the form and get instant access to an exclusive webinar on HP's Metal Binder Jetting 3D printing technology with exciting insights from INDO-MIM.Subscribe to our Newsletter
3DPresso is a weekly newsletter that links to the most exciting global stories from the 3D printing and additive manufacturing industry.
