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In aerospace, nuclear, medical and defence applications, protection against electromagnetic interference (EMI) and neutron radiation is essential. By penetrating deeply into materials, EMI corrupts data and causes malfunctions in critical on-board systems, while neutrons damage electronics at the atomic level and pose direct biological hazards to personnel -two threats that coexist in environments such as LEO satellites, nuclear power plant reactor cores, neutron- and proton-based medical therapy facilities, particle accelerators, and defence systems using compact nuclear reactors.

Until now, there has been a clear technological gap, as EMI and neutron radiation have required entirely separate shielding systems, resulting in heavier and more complex assemblies. However, a South Korean research team from the Korea Institute of Science and Technology (KIST) may well be changing the game. They have recently developed an ultrathin, stretchable, and 3D-printable complementary nanotubes-polymer composite film, capable of simultaneously attenuating EMI and neutron radiation in extreme environments. This work was published as a research article in the journal Advanced Materials on March 4, 2026.

This composite consists of complementary nanotube reinforcements enabling dual-mode shielding – single-walled carbon nanotubes (SWCNTs) for EMI shielding and boron nitride nanotubes (BNNTs) for neutron shielding –, which is further extended into a 3D-printed architecture using an intrinsically stretchable polydimethylsiloxane (PDMS) matrix.

“EMI shielding is an absorption-dominated mechanism: the percolated SWCNT network acts as the primary conductive pathway, where incoming electromagnetic waves induce oscillations of free electrons, leading to energy dissipation as heat through ohmic losses,” revealed Dr. Joo Yong-ho, who led the research at KIST’s Extreme Environment Shielding Material Research Center. “For neutron shielding, the mechanism is nuclear: BNNTs convert incoming thermal neutrons into harmless alpha particles and lithium nuclei through the reaction ¹⁰B + n → ⁴He + ⁷Li + γ, achieving approximately 72% attenuation at a thickness of 1 mm. Finally, PDMS matrix provides fracture strains exceeding 125%, stable shielding over 200 cyclic tensile strain cycles at 40% strain and across thermal extremes (–196 °C to 250 °C), and the viscoelastic behaviour required for 3D printability,” he added.

Regarding the fabrication, SWCNTs and BNNTs are first co-dispersed in an aqueous solution containing surfactant Triton X-100. “Their 1D nanotube morphological compatibility allows SWCNTs to spontaneously wrap around BNNT surfaces via van der Waals forces and dipolar interactions, forming a core–shell structure that maximizes interfacial contact,” as described by Dr. Joo. The nanotubes are then incorporated into a PDMS matrix dissolved in a THF-based organic solvent system and deposited layer by layer through direct ink writing, an extrusion-based 3D printing technique. This process enables the formation of ultrathin films with thicknesses of only 10-20 µm, well below the diameter of a human hair (~70 µm). “Moreover, honeycomb-pattern printing enhanced the shielding by approximately 10-15% compared with a flat film of the same thickness, as such a periodic geometry promotes multiple reflections of electromagnetic waves,” he added.

Ultrathin films drastically reduce weight and enable conformity to irregular or curved surfaces, unlike conventional thick, rigid shields. EMI shielding has traditionally relied on metals (e.g., copper, aluminum) or more recently carbon-based composites (e.g., graphene films and CNT-polymer systems), whereas neutron shielding has required hydrogen- or boron-rich materials such as polyethylene, boron carbide, lead, or concrete.

Consequently, this ultrathin material could serve as a conformal shielding layer in aerospace and defence systems, including LEO satellites and compact nuclear reactors. It could also find applications in medicine, such as boron neutron capture therapy, and in next-generation electronics, where it can be 3D-printed onto complex or curved surfaces.

Before industrial deployment, two key engineering challenges remain: “developing a scalable large-area fabrication process that ensures film uniformity and nanotube dispersion quality, and validating long-term durability under thermal cycling and mechanical fatigue,” said Dr. Joo. Additionally, partnerships with domestic manufacturers are “a natural near-term direction,” as KIST operates within a research support structure already connected to Korea’s space, semiconductor, and defence industries.

Hanna Siemiatycki
Editorial Contributor