Smart Foams: Boron Nitride‐Graphene Nanoplatelet Foams for Tunable Radiation Shielding and Strain Sensing

Abstract As space exploration advances, the demand for lightweight, multifunctional materials has substantially grown. Hybrid two‐dimensional (2D) material foams of different boron nitride nanoplatelets (BNNP)‐to‐graphene nanoplatelets (GNP) ratios are developed, which exhibit dual functionality: neutron radiation shields and strain sensors. The relationship between the composition, processing, microstructure, and their resultant neutron shielding and strain‐sensing properties are investigated. The hybrid foam properties can be finely tuned by adjusting BNNP:GNP compositions (1:0, 3:1, 1:1, 1:3, and 0:1). In terms of neutron radiation shielding, the mass absorption coefficient of hybrid foams increased with added BNNP, peaking at 14.9 cm² g⁻¹ for a pure BNNP foam. This mass absorption coefficient is 1.6 times that of pure GNP foams and almost 75 times that of aluminum. The radiation shielding properties are simulated using Geant4, a Monte Carlo‐based platform, and the simulations displayed a similar trend to the experimental results. The strain‐sensing properties of hybrid foams, measured by their gauge factor, exhibited exponential growth with rising GNP concentrations. Starting from the electrically insulating BNNP foam, the gauge factor increased to 53.4 with 25% GNP concentration and reached 201.8 for pure GNP foams. These findings highlight the versatility of the hybrid 2D material foams for space exploration.