Let us start by addressing the core first! What are LCEs? Well, LCEs stand for Liquid Crystalline Elastomers – crosslinked polymer networks that combine the elastic properties of rubber with the anisotropic properties of liquid crystals. The primary factor that drives their uniqueness is that multifunctionality and responsivity can be programmed into LCEs by patterning their local orientation.
It is a rare quality – hard to achieve in other monolithic material systems. And, as a Nature magazine review article from 2021 points out, advances in the synthesis and alignment of LCEs have made it possible to functionally integrate them in diverse fields, including robotics, optics, consumer products, energy, and healthcare.
Today, we delve deeper into this versatility of LCEs to see how they’re proving their worth in a range of fields, from Aerospace to HealthTech.
3D Printing Approach for Shape-Changing Materials Using LCE Structures
A team of researchers from Oregon State University has helped develop a new 3D printing approach for shape-changing materials. In real life, such shape-changing materials could help improve robotic applications by helping them acquire a robot-like quality.
While explaining the character of LCEs in this context, Devin Roach of the OSU College of Engineering said:
“LCEs are soft motors. Since they’re soft, unlike regular motors, they work great with our inherently soft bodies. So they can be used as implantable medical devices, for example, to deliver drugs at targeted locations, as stents for procedures in target areas, or as urethral implants that help with incontinence.”
More specifically, the research, as published in the journal Advanced Materials, details the preparation of LCEs by additive manufacturing (AM) techniques, predominantly using direct ink write printing. The researchers documented the preparation of aligned, main-chain LCEs via DLP 3D printing using a 100 mT magnetic field.
Systematic examination isolated the contribution of magnetic field strength, alignment time, and build layer thickness on the degree of orientation in 3D printed LCEs. The researchers concluded that the DLP printing of aligned LCEs could open new opportunities to fabricate stimuli-responsive materials in form factors optimized for functional use in soft robotics and energy absorption.
While all these might sound jargonish and full of high-tech implications, understanding LCEs could be much easier if we looked at their real-life applications. Essentially, LCEs can change their shapes in response to exposure to certain stimuli, like heat. Leveraging this property, LCEs can be used to transfer thermal energy into mechanical energy so that it can be stored and used on demand.
The muscle-like flexibility that the LCEs introduce us to can help us move forward significantly in the area of soft robotics. These flexible robots could enter areas that are unsafe or unfit for humans. According to Devin Roach:
“They have also been shown to have promise in aerospace as actuators for automated systems such as those for deep space grappling, radar deployment, or extraterrestrial exploration.”
DLP, the core achievement of this research, which was carried out by Roach and collaborators at Harvard University, the University of Colorado, and Sandia and Lawrence Livermore national laboratories, showed us a way to align the molecules using a magnetic field during a type of 3D printing called digital light processing. It was crucial to leverage LCEs to their fullest potential because the shape-changing properties of the liquid crystalline elastomers were dependent on the alignment of the molecules within the materials. Digital Light Processing leverages light to harden liquid resin into solid shapes with precision.
While highlighting the achievements of the study, Roach said that aligning the molecules could be the key to unlocking the LCE’s full potential and enabling their use in ‘advanced, functional applications.” Roach went on further to assert that their work opened up “new possibilities for creating advanced materials that respond to stimuli in useful manners, potentially leading to innovations in multiple fields.”
Roach and his fellow collaborators studied a range of parameters. They varied the strength of the magnetic field and looked into how it could impact the molecular alignment along with other factors, such as the printed layer’s thickness. The researchers could print complicated liquid crystalline elastomer shapes that change in specific ways when heated.
Roach also led a different team of researchers to further look into the mechanical damping potential of LCEs. The research and its findings could prove useful in developing best-in-class automatic shock absorbers, seismic dampers, and vibration dampers on bridges.
While the research and its findings could help LCEs become instrumental in many areas, research around Liquid Crystalline Elastomer structures has been continuing for quite some time now. In the next couple of segments, we shall discuss a few such studies and how they could have an impact on technological innovations around us.
LCE and 4D Printing
In June 2022, a research article published in the journal Materials Horizons, scientists showed that by patterning order to structures, LCEs demonstrate reversible high-speed and large-scale actuation in response to external stimuli, allowing for close integration with 4D printing and architectures of digital devices, which is scarcely observed in homogeneous soft polymer networks.
The researchers collected information about recent advances in 4D printing of LCEs, with emphasis on synthesis and processing methods that enabled microscopic changes in the molecular orientation and hence brought macroscopic changes in the properties of end-use objects. The research inferred that the LCE-4D printing combine could prove useful in the fields of soft robotics, optics, and biomedical devices.
Performance of LCEs on Biological Cell Response
Another research, published in the journal ACS Applied Polymer Materials in January 2023, looked into the structures and synthesis methods of LCEs as well as their material biology with an emphasis on biochemical and biomechanical features of cells from a molecular view. The research, quite crucially, investigated factors such as the quasi-liquid crystalline behavior of cells, the degree of orientational order in different cells, and liquid crystalline-induced topographical signals as growth-enhancing agents for cells.
Apart from such research by scholars in the field, reputed research labs across the world have also shown interest in LCEs and their evolution. We discuss a couple of such research labs in the following segments and try to understand why they consider LCEs crucial.
LCE Evaluation by Nguyen Lab: Johns Hopkins Whiting School of Engineering
The lab believes that the viscoelastic properties of LCEs can be exploited to design transformative materials and structures with extreme dissipation behavior. The lab carried out a study to develop a fundamental understanding of the relaxation mechanisms of main-chain LCEs to enable the design of extraordinary dissipation behaviors of LCE materials and structures over multiple length scales.
The researchers hypothesized that the enhanced dissipation behavior of LCEs arises from the coupling of the relaxation dynamics of the mesogens and polymer network and depends on the mesogen order and chain alignment. According to the lab, intrinsic dissipation behavior could be exploited in an architected design to produce structures with extreme damping and energy absorption.
Harvard University’s Aizenberg Laboratory’s Work on LCEs
The vision of the lab was to look at LCEs as adaptive materials with molecular scale programmability that could generate opportunities for the rational design of next-generation responsive materials and potentially transform areas ranging from artificial muscles to self-cleaning surfaces and homeostatic systems.
The lab found LCEs to be promising materials in achieving the desired programmability and deformation capabilities as they consisted of anisotropic molecules known as mesogens, covalently bound to a polymeric background material (the elastomer).
While a variety of approaches existed to prescribe the alignment of the mesogens, the Aizenberg group typically employed magnetic fields to impose the liquid crystal director. This method could be applied to and programmed within any 3D shape, allowing the researchers to encode macroscopic deformation modes at the molecular level.
The Aizenberg group, active as a biomineralization and biomimetics lab under the flagship of Harvard John A. Paulson School of Engineering and Applied Sciences, has used magnetically aligned LCEs to create a variety of multi responsive microstructures such as micro-posts, microplates, interconnected cellular structures, and closely spaced arrays.
The group is looking forward to moving ahead with its research to expand our fundamental understanding of self-regulated systems, as well as expanding these designs into applications such as autonomous multimodal actuators in switchable adhesives, information encryption, autonomous antennae, energy harvesting systems, soft robots, and smart buildings.
While individual research and lab-based research work on LCEs are in full swing, some companies can benefit from it. We will now look at a couple of such companies.
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1. 3D Systems Corp (DDD -3.23%)
The company that comes to the top of the list when we think about leveraging research around LCEs on a commercial scale is 3D Systems Corp. It covers the entire spectrum of the 3D printing industry, starting from 3D printers, materials, and software. It has the industry’s most comprehensive range of commercial 3D printers, enabling companies to print plastic or metal parts at the point of need in a fraction of the time compared to traditional manufacturing processes.
The company’s extensive and versatile portfolio of 3D printing materials includes plastic, elastomer, composite, wax, metal, bio-compatible, and more. Furthermore, it adds value to the entire system through its AI-powered software, which is tailored for precision in additive manufacturing and is ideal for industrial and healthcare applications.
The company serves the widest possible range of clients in industries such as aerospace and defense, automotive, bioprinting, carbon capture, consumer technology, and many more.
The company has a bouquet of products in the elastomer category, including the DulaForm TPU Elastomer, which is a thermoplastic elastomer material with rubber-like flexibility and functionality. It can be used for low to medium-lot production of consumer goods, manufacturing flexible parts for industrial applications, creating functional prototypes of hoses and seals, and the prototyping and production of footwear components.
3D System Corp VisiJet® CE-NT material delivers best-in-class elastomeric material performance for functional prototyping to meet a range of engineering and design applications. It has great tensile properties, and its translucent natural color helps create life-like models of human anatomy for medical modeling applications.
3D Systems Corporation (DDD -3.23%)
3D Systems Corporation announced its financial results for the third quarter ended September 30, 2024, on November 26, 2024. Although its revenue of $112.9 million witnessed a decrease of 9% year-over-year, customer interest in 3D printing applications continued to gain momentum, with revenues in the Application Innovation Group (AIG) growing over 26% year-to-date versus prior year across industrial markets.
2. Teradyne, Inc.(TER -2.71%)
Teradyne, Inc. makes equipment that tests semiconductors, wireless devices, and other complex electronics. Their tools are used in industries like automotive, aerospace, defense, and consumer electronics. They’re a major player in the world of automated testing and industrial automation.
Teradyne, Inc. (TER -2.71%)
For the third quarter of 2024, the company reported $737 million in revenue. The bulk of it—$543 million—came from Semiconductor Test, with Robotics adding $89 million. Smaller contributions came from System Test and Wireless Test at $73 million and $33 million, respectively.
Liquid Crystalline Elastomers (LCEs) could play a big role in shaping Teradyne’s future, especially in robotics. LCEs are special because they can change shape when exposed to heat or light. This makes them ideal for soft robotics, which need flexibility and precision. If Teradyne integrates LCEs into their robots, it could make them more adaptable for industries that demand advanced automation.
3. Zebra Technologies Corporation (ZBRA -1.69%)
Zebra Technologies Corporation stands out in enterprise asset intelligence, with their mobile computers, barcode scanners, RFID readers, and specialty printers, used in industries like retail, healthcare, manufacturing, and logistics.
Zebra Technologies Corporation (ZBRA -1.69%)
In the third quarter of 2024, Zebra reported revenue of $1.26 billion, a 31% increase from the previous year. Adjusted earnings per share came in at $3.49, beating expectations and showing strong growth.
Liquid Crystalline Elastomers could be an interesting addition to Zebra’s portfolio, as these materials change shape when exposed to heat or light, making them ideal for use in soft robotics or other adaptive systems. If Zebra explores this technology, it might enhance the adaptability of their solutions—something industries requiring flexible automation could find valuable. LCEs could let Zebra’s systems work in more complex environments or handle tasks that traditional materials can’t.
The future of LCEs
LCEs are unique materials in the sense that they fuse the anisotropic behavior of liquid crystals and the rubber elasticity of lightly crosslinked polymers. Traditional shape memory materials are not as effective as LCEs in building soft actuators. LCEs have extraordinary mechanical properties, good flexibility, anisotropic behavior, and reversible shape responses.
However, research around LCEs needs to address multiple loopholes to realize their potential to the fullest. Researchers have found that for soft materials, such as LCEs, there is often a trade-off relationship between the features of “high actuation stress“ and “large actuation strain,“ both of which are key factors determining their actuating performances.
The researchers have also identified that since most LCEs are thermotropic, it is difficult to realize their multi-stimulus responses and remote control, such as light-driven actuators. A majority of the ongoing research in the field focuses on physically doing a variety of functional nano-fillers (photothermal, electrothermal nano-materials, etc.) into LCE matrices to address these issues.
However, there is doubt among researchers that the poor dispersibility of the functional fillers in the LCE matrix and the weak filler–matrix interaction may result in phase separation in composites, resulting in a dampened performance of the resulting actuators.
While our present research is a well-meaning step in that direction, there are doubts about the basic understanding of the relationship between molecular arrangement and action property of LCEs. Researchers see it as a challenge to accurately control the deformation or motion of LCEs.
The novel 3D and 4D printing technologies that have been developed to process LCEs into sophisticated architectures are still aimed at building customized equipment with no good solution for mass production so far.
However, on the positive side, interest in LCEs in the science and technology world is visible. There is a growing deployment of LCEs in building up smart devices.
With growing interest in new types of LCE materials, advanced 3D micro/nanofabrication technologies, novel action schemes, and sophisticated manipulation strategies, LCE-based actuators may achieve rapid advancements and find more cutting-edge applications soon.
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