In a groundbreaking advance poised to revolutionize materials science and telecommunications, researchers from Imperial College London, the University of Michigan Engineering, and Tufts University have pioneered a method to transform silk threads into robust, transparent, plastic-like materials capable of manipulating terahertz radiation—an electromagnetic spectrum crucial for the next generation of wireless communications, notably 6G networks. This novel technique not only conserves the intrinsic crystalline architecture of natural silk but also minimizes the environmental footprint traditionally associated with silk processing, marking a significant leap toward sustainable high-performance materials.
Silk, historically celebrated for its unique combination of strength and flexibility, owes these properties to its intricate molecular composition. The fibers consist of long chains of amino acids that create a hierarchical microstructure characterized by alternating ordered crystalline domains and amorphous regions. This sophisticated architecture imparts exceptional toughness and pliancy, attributes that the research team has ingeniously preserved and augmented through precise thermal and pressure treatments. By applying temperatures between 257 and 419 degrees Fahrenheit and pressures spanning from 1,900 to 9,800 atmospheres, they induced the fusion of silk threads where the amorphous segments coalesce into uniform sheets without compromising the delicate crystalline folds. This preservation of silk’s native structure is a critical factor underpinning the composite’s remarkable optical and mechanical performance.
Traditional methodologies for fabricating silk-based plastics typically involve dissolving silk fibers in chemical solvents and reconstituting them into powders before thermally processing into materials. While effective to some extent, these techniques disrupt the crystalline domains, diminishing the desirable mechanical and optical properties of the resultant materials. Contrastingly, the method developed by this team circumvents the necessity of harsh chemical solvents, instead relying on a streamlined, one-step process involving only a crucial boiling step to eliminate sericin, the natural binding protein surrounding silk fibers. This streamlined processing not only mitigates the use of environmentally deleterious chemicals but also enables the recycling of shorter and fragmented silk fibers previously deemed unsuitable for textile reweaving, thereby contributing to waste reduction in the fashion and textile industries.
From a mechanical perspective, the fused silk composites exhibit impressive toughness that rivals or exceeds many metal alloys and conventional petroleum-derived plastics. Their puncture resistance aligns closely with that of carbon-fiber-reinforced polymers commonly employed in aerospace and automotive industries—a benchmark that underscores their potential in demanding applications such as sports equipment, shipping containers, and specialized packaging. Moreover, early in vivo studies demonstrate the material’s biodegradability, as evidenced by its gradual degradation when implanted in murine models, hinting at promising applications in transient medical implants that naturally dissolve after fulfilling their functional role.
The optical prowess of these silk-based materials further elevates their technological significance. The composite exhibits the rare ability to rotate or polarize terahertz frequencies of light, a spectrum range integral to proposed 6G telecommunications infrastructure. Terahertz waves promise data transmission speeds hundreds of times faster than current 5G networks and hold particular promise for delivering high-speed internet to remote and rural regions. Typically, bioderived materials exhibit strong terahertz absorption, impeding light traversal and limiting their practical use in photonics. However, the crystalline preservation and structural optimization achieved in these silk materials facilitate controlled elliptic polarization of terahertz light—an advanced optical modulation crucial for encoding data across additional channels and vastly expanding communication bandwidth.
Critically, the researchers illustrated that by delicately adjusting the thermal and pressure parameters during fabrication, they could fine-tune the degree of optical twist imparted to terahertz waves. This tunability represents a rare feat in material science, enabling customized optical responses vital for diverse applications spanning from wireless communications to advanced sensor technologies. According to co-corresponding author Professor Nicholas Kotov from the University of Michigan, this amalgamation of transparency and pronounced terahertz optical activity in a bioderived composite is unprecedented, heralding a new class of multifunctional materials.
Addressing sustainability concerns, this innovative approach excels by dramatically cutting down water, chemical, and salt usage in silk processing compared to conventional methods. The research team intentionally designed the process to harness silk’s intrinsic qualities without extensive chemical alteration, promoting circularity in textile waste management. By facilitating the reuse of even minuscule silk fibers through mechanical fusion, the process extends the lifecycle of silk products, presenting a viable alternative to waste-inducing disposal and landfill strategies.
Looking ahead, the team is focused on scaling this manufacturing process to accommodate larger and more complex geometries suitable for commercial production. Concurrently, comprehensive lifecycle assessments are underway to quantitatively verify the environmental benefits associated with this green fabrication pathway. Efforts are also concentrated on integrating these fused silk materials into practical devices, including sensors, and collaboration with industrial partners is being actively sought to transition this promising science from laboratory innovation to market-ready technology.
This study, published in Nature Sustainability, is supported by a constellation of funding sources including the University of Michigan’s Center for Complex Particle Systems (COMPASS), the National Science Foundation, the Air Force Office of Scientific Research, the UK’s Engineering and Physical Sciences Research Council, and Tufts University’s Launchpad Accelerator grant. Such broad backing underscores the cross-disciplinary and global significance of this advancement with potential ramifications spanning sustainable materials science, photonics, and telecommunications.
To summarize, this innovative fusion of silk threads into mechanically robust, lightweight, and terahertz-active materials marks a transformative juncture in both applied biomaterials and next-generation communications. By marrying the age-old natural wonder of silk’s microstructure with cutting-edge fabrication techniques, this research offers a visionary pathway toward sustainable high-performance materials that may soon underpin critical technologies in 6G networks and beyond.
Subject of Research:
Silk-based hierarchical composite materials with optical activity in the terahertz range for advanced telecommunications and sustainable applications.
Article Title:
Hierarchical Materials from Fused Silk: Unlocking Terahertz Optical Activity for 6G and Beyond
News Publication Date:
2024
Web References:
https://www.nature.com/articles/s41893-026-01821-y
https://ieeexplore.ieee.org/document/10643251
https://www.cnet.com/home/internet/i-saw-the-future-of-internet-technology-while-atop-a-cell-tower-in-rural-washington/
References:
Kotov, N., Li, C., Bilotti, E., et al. (2024). Hierarchical materials from fused silk. Nature Sustainability. DOI: 10.1038/s41893-026-01821-y
Image Credits:
Not provided
Keywords:
Silk, sustainable materials, terahertz radiation, 6G communications, biodegradable composites, crystalline polymers, optical activity, material engineering, photonics, waste reduction, textile recycling, biodegradable implants
