A groundbreaking development in 3D printing techniques for shape-changing materials has emerged from Oregon State University (OSU), harnessing innovations that could transform applications in robotics, biomedical devices, and energy systems. The initiative is spearheaded by Devin Roach, an assistant professor of mechanical engineering at OSU, along with collaborators from prestigious institutions including Harvard University, the University of Colorado, and Sandia and Lawrence Livermore national laboratories.
Liquid crystalline elastomers (LCEs), the focus of this research, are advanced materials capable of dramatic shape transformations in response to external stimuli such as heat. Roach describes these materials as "soft motors," noting their adaptability which makes them especially favourable for use in soft-bodied applications like medical implants. Potential functionalities include targeted drug delivery systems, stents for minimally invasive procedures, and implants aimed at addressing issues like incontinence.
LCEs are defined by their unique structural properties. They consist of lightly crosslinked polymer networks that can convert thermal energy—derived from sources like solar power or alternating currents—into mechanical energy, which can be harnessed for practical use. In the realm of soft robotics, Roach outlines their potential for exploration in hazardous environments unsuitable for human activity, and hints at possible aerospace applications for tasks such as radar deployment or traversing extraterrestrial landscapes.
The effective use of LCEs rests on their anisotropy and viscoelasticity traits. Anisotropy refers to their directionally dependent strength, analogous to wood being more robust along its grain than across it. In contrast, viscoelastic materials exhibit both viscous properties, resisting deformation, and elastic qualities, allowing them to revert to their initial shape post-stress.
Central to advancing this technology is the ability to align the molecules within the LCEs during the 3D printing process, specifically using a technique called digital light processing. This method, which employs light to solidify liquid resin into precise shapes, encounters challenges in achieving proper molecular alignment. "Aligning the molecules is the key to unlocking the LCEs' full potential and enabling their use in advanced, functional applications," Roach stated, emphasising the significance of this element in the research.
The team's investigations included varying the strength of magnetic fields and examining how these and other elements, like the thickness of printed layers, influenced molecular alignment. The outcome was a series of complex shapes capable of specific transformations upon heat exposure, paving the way for potential breakthroughs in diverse fields.
This pivotal study has been highlighted in the journal Advanced Materials, bolstered by support from the National Science Foundation and the Air Force Office of Scientific Research. Furthermore, Roach leads another significant project, detailed in the journal Advanced Engineering Materials, examining the mechanical damping properties of LCEs—essential for applications like automotive shock absorbers and earthquake-resistant structures.
A collaborative effort involving OSU students Adam Bischoff, Carter Bawcutt, and Maksim Sorkin, alongside researchers from Sandia, Lawrence Livermore, and Navajo Technical University, demonstrated that a novel fabrication approach known as direct ink writing can create effective mechanical damping devices. These devices are capable of dissipating energy across a wide range of loading rates, further enhancing the utility of LCEs in practical applications.
The advancements in LCE technology and 3D printing techniques mark a pivotal step forward in the evolution of intelligent materials, poised to significantly impact various industries in the near future.
Source: Noah Wire Services