A researcher has played a key role in developing a novel 3D printing technique for materials capable of changing shape, which are compared to muscles. This advancement is set to enhance applications in robotics, healthcare, and energy systems.
An Oregon State University researcher has contributed to the creation of a new 3D printing method for materials that can alter their shape, similar to muscles, paving the way for better uses in robotics as well as biomedical and energy technologies.
The liquid crystalline elastomer structures designed by Devin Roach from the OSU College of Engineering, along with his collaborators, can crawl, fold, and snap right after being printed.
“LCEs essentially act like soft motors,” explained Roach, an assistant professor of mechanical engineering. “Their softness allows them to function well within our naturally soft bodies. This makes them suitable for medical implants that deliver drugs to specific sites, serve as stents in targeted procedures, or function as urethral implants for incontinence issues.”
Liquid crystalline elastomers are lightly linked polymer networks that can change shape dramatically when exposed to certain triggers, such as heat. They have the ability to convert thermal energy (from sources like sunlight or electrical currents) into mechanical energy that can be stored for later use. Additionally, LCEs could significantly impact the field of soft robotics, Roach pointed out.
“Flexible robots using LCEs might venture into areas where human presence is hazardous or inappropriate,” he noted. “They also hold potential in aerospace, serving as actuators for automated systems employed in deep space activities, radar operation, or exploration beyond Earth.”
The effectiveness of liquid crystalline elastomers hinges on their unique combination of anisotropy and viscoelasticity, according to Roach.
Anisotropy describes a directional dependence, like how wood is stronger along its grain than across it. Viscoelastic materials, on the other hand, are both viscous—like honey, which resists flow and slowly deforms under pressure—and elastic, as they return to their original shape after the stress is removed, similar to rubber. These materials deform gradually and also recover slowly.
The shape-shifting capabilities of liquid crystalline elastomers depend on how their molecules are aligned. Roach and his team from Harvard University, the University of Colorado, and Sandia and Lawrence Livermore national laboratories found a method to align these molecules using a magnetic field during a specific type of 3D printing known as digital light processing.
3D printing, or additive manufacturing, produces objects layer by layer. In digital light processing, light is employed to solidify liquid resin into precisely crafted shapes. However, aligning the elastomers’ molecules can be difficult.
“Molecule alignment is crucial to fully harnessing the potential of LCEs, making them suitable for advanced functional applications,” Roach remarked.
Roach and his colleagues experimented with different magnetic field strengths and investigated how they, along with other factors like printed layer thickness, influenced molecular alignment. This research enabled them to create complex liquid crystalline elastomer shapes that alter in specific ways when exposed to heat.
“Our findings create new opportunities for developing advanced materials that react to various stimuli in beneficial ways, potentially leading to new breakthroughs in numerous industries,” Roach stated.
The study, published in Advanced Materials, received support from the National Science Foundation and the Air Force Office of Scientific Research.
In related work, published in Advanced Engineering Materials, Roach led a team from Oregon State and collaborated with Sandia, Lawrence Livermore, and Navajo Technical University to investigate the mechanical damping capabilities of liquid crystalline elastomers.
Mechanical damping involves the reduction or dissipation of energy produced by vibrations or oscillations in mechanical environments, including car shock absorbers, seismic dampers that safeguard buildings during earthquakes, and vibration dampers on bridges that reduce oscillations caused by winds or traffic.
OSU students Adam Bischoff, Carter Bawcutt, and Maksim Sorkin, alongside the research team, demonstrated that a fabrication technique known as direct ink write 3D printing can effectively create mechanical damping devices that dissipate energy across a wide range of loading conditions.
