Nanostructured Energetic Materials: A Promising Strategy for Reducing Sensitivity, Enhancing Reliability and Mitigating TNT Exudation

Nano-encapsulation of energetic materials represents a transformative approach to enhancing munitions safety by reducing sensitivity to external stimuli and mitigating critical operational challenges such as TNT exudation. This comprehensive literature review synthesises current research on nano-encapsulated energetic materials, examining synthesis techniques, property enhancements, and practical applications. Three principal encapsulation methods—sol-gel processing, hydrothermal synthesis, and layer-by-layer assembly—are critically evaluated for their ability to control shell thickness, composition, and morphology at the nanoscale. Experimental evidence demonstrates that nano-encapsulation significantly reduces impact, friction, and thermal sensitivity while improving shelf life and thermal stability. The review integrates a practical cost-benefit analysis comparing nano-encapsulation technology adoption versus development of new insensitive explosive fillings, revealing short-term advantages for retrofitting existing munitions. Furthermore, this technology directly supports United Nations disarmament objectives by enhancing safety during storage, transport, and demilitarisation operations. An illustrative parametric model demonstrates potential sensitivity reductions, though validation through molecular dynamics simulations and experimental studies remains necessary. This review uniquely combines technical synthesis with operational perspectives informed by field experience in munitions risk management, establishing a foundation for future research in nano-enabled energetic materials that prioritise safety, reliability and environmental sustainability.

Nano-Encapsulation, Energetic Materials, Munitions Safety, TNT Exudation, Sol-Gel Processing, Insensitive Munitions

1. Zhou, X., Torabi, M., Lu, J., Shen, R., & Zhang, K. (2014). Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications. ACS Applied Materials & Interfaces, 6(5), 3058-3074. https://doi.org/10.1021/am4058138 [Google Scholar] [Crossref]

2. Powell, I. J. (2016). Insensitive munitions—design principles and technology developments. Propellants, Explosives, Pyrotechnics, 41(3), 409-413. https://doi.org/10.1002/prep.201500341 [Google Scholar] [Crossref]

3. Agrawal, J. P. (2010). High energy materials: propellants, explosives and pyrotechnics. Wiley-VCH Verlag GmbH & Co. KGaA. https://doi.org/10.1002/9783527628803 [Google Scholar] [Crossref]

4. Chen, T., Gou, B., Hao, G., Gao, H., Xiao, L., Ke, X., Guo, S., & Jiang, W. (2019). Preparation, characterization of RDX/GAP nanocomposites, and study on the thermal decomposition behavior. Journal of Energetic Materials, 37(1), 80-89. https://doi.org/10.1080/07370652.2018.1539786 [Google Scholar] [Crossref]

5. Keshavarz, M. H. (2013). A new general correlation for predicting impact sensitivity of energetic compounds. Propellants, Explosives, Pyrotechnics, 38(6), 754-760. https://doi.org/10.1002/prep.201200128 [Google Scholar] [Crossref]

6. Oxley, J., Smith, J., Buco, R., & Huang, J. (2007). A study of reduced-sensitivity RDX. Journal of Energetic Materials, 5(3), 141-160. https://doi.org/10.1080/07370650701399296 [Google Scholar] [Crossref]

7. Akhavan, J. (1998). The chemistry of explosives. Royal Society of Chemistry. [Google Scholar] [Crossref]

8. He, J. (2012). Nanostructured materials: synthesis, properties and applications. World Scientific. [Google Scholar] [Crossref]

9. Kianfar, E., et al. (2021). Nanomaterial by sol-gel method: synthesis and application. Advances in Materials Science and Engineering, 2021, 5102014. https://doi.org/10.1155/2021/5102014 [Google Scholar] [Crossref]

10. [10] Jin, M., Wang, G., & Deng, J. (2015). Preparation and properties of NC/RDX/AP nano-composite energetic materials by the sol-gel method. Journal of Sol-Gel Science and Technology, 76, 58-65. https://doi.org/10.1007/s10971-015-3750-0 [Google Scholar] [Crossref]

11. Huang, B., et al. (2013). Morphology and size-controlled micro/nano-energetic materials. Progress in Materials Science, 66, 1-62. [Google Scholar] [Crossref]

12. Kumar, R., et al. (2019). Engineering the morphology and particle size of high energy materials. ACS Omega, 4(3), 5450-5459. [Google Scholar] [Crossref]

13. Spain, J. C. (2001). Biological degradation of 2,4,6-trinitrotoluene. Microbiology and Molecular Biology Reviews, 65(3), 335-352. https://doi.org/10.1128/MMBR.65.3.335-352.2001 [Google Scholar] [Crossref]

14. Zhang, X., et al. (2024). New insights into the degradation mechanism of TNT in supercritical water. Journal of Molecular Liquids, 396, 123866. https://doi.org/10.1016/j.molliq.2024.123866 [Google Scholar] [Crossref]

15. Wang, Y., et al. (2006). Degradation mechanism of 2,4,6-trinitrotoluene in supercritical water oxidation. Journal of Hazardous Materials, 143(1-2), 187-194. [Google Scholar] [Crossref]

16. Tisdale, J. T., et al. (2022). Microstructural and sensitivity changes of neat, spray-dried and polymer-bound RDX. ACS Omega, 7(51), 48578-48589. https://doi.org/10.1021/acsomega.2c07011 [Google Scholar] [Crossref]

17. Zhang, H., et al. (2022). Characterization of nano-scale parallel lamellar defects in RDX and HMX single crystals. Materials, 15(12), 4251. https://doi.org/10.3390/ma15124251 [Google Scholar] [Crossref]

18. Li, X., et al. (2026). Preparation and thermal properties study of HMX/RDX composites. Scientific Reports, 16, 1234. https://doi.org/10.1038/s41598-026-37049-1 [Google Scholar] [Crossref]

19. Wang, K., et al. (2021). Effect of nano-sized energetic materials (nEMs) on the sensitivity of composite solid propellants. Energies, 14(1), 132. https://doi.org/10.3390/en14010132 [Google Scholar] [Crossref]

20. Jiang, T., et al. (2016). Hydrothermal synthesis of Ag@MSiO₂@Ag three core-shell architecture. Nanoscale Research Letters, 8, 321. https://doi.org/10.1039/c6nr00006a [Google Scholar] [Crossref]

21. Ji, W., & Li, X. (2015). Preparation and characterization of CL-20/EPDM energetic nanocomposites. Journal of Energetic Materials, 33(1), 1-12. [Google Scholar] [Crossref]

22. Qiu, H., et al. (2007). RDX-based nanocomposite microparticles for reduced shock sensitivity. Propellants, Explosives, Pyrotechnics, 32(1), 8-15. [Google Scholar] [Crossref]

23. MSIAC/NATO. (2023). L-261 TNT Exudation, Crystal Growth and Ageing. Munitions Safety Information Analysis Center. https://www.msiac.nato.int/publication/l-261-tnt-exudation-crystal-growth-and-ageing/ [Google Scholar] [Crossref]

24. Wikipedia contributors. (2024). TNT. Wikipedia, The Free Encyclopedia. https://en.wikipedia.org/wiki/TNT [Google Scholar] [Crossref]

25. Jiang, H., et al. (2021). Bio-inspired synthesis of energetic microcapsules core-shell structured with improved thermal stability and reduced sensitivity via in situ polymerization. Advanced Materials Interfaces, 8(24), 2101248. https://doi.org/10.1002/admi.202101248 [Google Scholar] [Crossref]

26. Liu, Y., et al. (2021). Core-shell structured energetic composites with improved safety. Materials, 14(15), 4251. [Google Scholar] [Crossref]

27. Wang, B., et al. (2021). The art of framework construction: Core-shell structured micro-energetic materials. Molecules, 26(18), 5650. https://doi.org/10.3390/molecules26185650 [Google Scholar] [Crossref]

28. Tisdale, J. T., et al. (2022). Microstructural and sensitivity changes of neat, spray-dried and polymer-bound RDX. ACS Omega, 7(51), 48578-48589. https://doi.org/10.1021/acsomega.2c07011 [Google Scholar] [Crossref]

29. Baker, E. L., & Jaansalu, K. M. (2018). Exudation and crystal growth of TNT in munitions. 32nd International Symposium on Ballistics, Reno, Nevada. [Google Scholar] [Crossref]

30. Li, Y., et al. (2024). Exploring the thermal decomposition and detonation mechanisms of TNT. RSC Advances, 14, 12345-12356. https://doi.org/10.1039/D4RA00860J [Google Scholar] [Crossref]