Ultrathin, stretchable, and 3D-printable nanotube composites can shield electronics from both electromagnetic interference (EMI) and neutron radiation in extreme environments.
Study: Ultrathin, Stretchable, and 3D-Printable Complementary Nanotubes–Polymer Composites for Multimodal Radiation Shielding in Extreme Environments. Image Credit: Wanut Sawangwong/Shutterstock.com
In a study published in Advanced Materials, researchers combined single-walled carbon nanotubes (SWCNTs) with boron nitride nanotubes (BNNTs) to create a lightweight shielding system with two complementary roles: SWCNTs suppress electromagnetic interference, while BNNTs absorb neutrons.
The team first demonstrated the concept in ultrathin hybrid nanotube films, then extended it into a stretchable, 3D-printable polymer composite. The work points to a promising route for shielding materials in aerospace, nuclear, medical, and defense technologies, where conventional protection is often too heavy or rigid.
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Electronic systems operating in space, nuclear facilities, medical radiation settings, and defense environments face two persistent threats: electromagnetic interference and high-energy neutron radiation. Both can disrupt or damage sensitive components, reducing reliability in conditions where failure may be costly or dangerous.
Traditional shielding materials, including metals and concrete, can provide effective protection, but they are heavy, inflexible, and poorly suited to lightweight or deformable electronics. That has become a growing problem as devices become smaller, lighter, and more adaptable, particularly in flexible electronics and wearable systems.
Two Nanotubes, Two Jobs
The material system is built around two nanotube types with different strengths. SWCNTs are electrically conductive and effective at attenuating electromagnetic waves. BNNTs, meanwhile, contain boron atoms with a high neutron absorption cross-section, making them well-suited to neutron shielding.
Previous studies had largely examined these materials separately. Here, the researchers combined them into a single multifunctional system designed to address both challenges at once.
Creating the Material
The team first dispersed SWCNTs and BNNTs in solution using surfactants to produce stable suspensions and uniform mixing. Free-standing hybrid films were then made by vacuum filtration, yielding structures typically 10 to 20 µm thick.
Microscopy showed a coaxial architecture in which SWCNT bundles wrapped around BNNT cores. Raman spectroscopy and Fourier-transform infrared spectroscopy indicated strain interactions between the two nanotube systems, while elemental mapping confirmed the distribution of boron, nitrogen and carbon throughout the hybrid structure.
To make printable composites, the researchers then incorporated the nanotube network into a polydimethylsiloxane (PDMS) elastomer matrix. The resulting ink was processed by direct ink writing, an extrusion-based 3D-printing method that enables layer-by-layer fabrication of complex geometries. Rheological testing showed that the ink had the viscoelastic properties needed for printing.
Further measurements, including conductivity tests, thermogravimetric analysis, and neutron attenuation experiments, were used to evaluate electrical, thermal, and mechanical performance.
Study Results
The hybrid nanotube films formed a dense, interconnected network with strong interfacial contact and continuous conductive pathways. That structure supported charge transport and underpinned the material’s electromagnetic shielding performance.
In the X-band frequency range, the neat hybrid films achieved EMI shielding effectiveness above 50 dB at micrometer-scale thicknesses. The shielding was mainly absorption-dominated rather than reflection-dominated: energy was dissipated primarily through ohmic losses in conductive SWCNT pathways, with interfacial polarization playing a secondary role.
The study also found that percolated SWCNT networks persisted across a wide range of compositions, helping preserve EMI shielding even when BNNT content was high.
For neutron shielding, a composite with an SWCNT:BNNT ratio of 2:8 achieved a neutron attenuation coefficient of about 1.27 mm-1, corresponding to roughly 72 % attenuation at a thickness of 1 mm. That performance was driven mainly by boron atoms in the BNNT structure.
Thin Films and Printable Composites
When the nanotube network was embedded in PDMS, the material became stretchable and printable while retaining useful shielding performance. Mechanical tests showed fracture strains above 125 %, and EMI shielding remained stable through repeated deformation cycles. Thermal testing showed structural stability from cryogenic temperatures near −196 °C to elevated temperatures around 250 °C.
In this polymer-composite form, EMI shielding effectiveness reached up to about 23 dB at sub-millimeter thicknesses. That is lower than the performance reported for the neat nanotube films, but still significant for flexible applications where printability and mechanical compliance matter.
Architecture Also Changes Performance
The study suggests shielding depends not only on composition but also structure. Using direct ink writing, the team produced geometrically tunable designs, including honeycomb lattices. These architectures increased electromagnetic attenuation by promoting multiple internal reflections.
The authors present this as an encouraging early result rather than a final optimisation, but it shows how additive manufacturing could be used to tune shielding performance through geometry as well as material chemistry.
The Bigger Picture
Taken together, the findings outline a practical strategy for multifunctional shielding in harsh environments. The neat hybrid films delivered the strongest combined EMI and neutron shielding, while the 3D-printable PDMS composites offered a more flexible and application-oriented version of the same concept.
The broader significance lies in combining low weight, mechanical durability, thermal resilience, and dual shielding in a single platform. That could make the approach useful for future electronic systems that need reliable protection in demanding operating conditions.
Journal Reference
Flandy, Kim, K., et al. (2026). Ultrathin, Stretchable, and 3D-Printable Nanotubes-Polymer Composites for Multimodal Radiation Shielding in Extreme Environments. Advanced Materials, e13805. DOI: 10.1002/adma.202513805
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