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esult of a thermonuclear explosion or an E-bomb presents a real threat to the security of
critical information infrastructures. Research efforts in the shielding of electronic
components concentrate on the realization of passive material systems for the
neutralization of electromagnetic radiation.
Nanostructured materials for electrostatic shielding and absorbing microwaves are being
investigated as part of the development of antireflection and optical interference coatings
in both the visible and ultraviolet spectra. Among other things, important efforts are
being made towards the development of innovative radar stealth coatings. The most
significant procedures for the realization of antistatic or absorbent coatings are based on
carbon nanotube polymer composites, nanocomposites made from transitional metal
mixed oxides in a polymer matrix, and cenospheres (hollow porous ceramic spheres
coated in a metallic nanoscale coating). The development of targeted dynamic shielding
technologies is also being discussed. Such technologies involve the selective generation
of electromagnetic absorption bands using the combination of mutually interacting
nanoparticles in an absorption coating. These bands can then be modulated and
controlled externally.
One example of the numerous international research projects dealing exclusively with the
modification of carbon nanotube-based materials for use in security applications is the
thin polymer layer system developed at the Korea University in Seoul. This system is
suitable for being used as an EMI (Electromagnetic Interference) shielding system for
electronic components, among other things. In relation to the development of flexible
nanocomposites coating, tests have been carried out using different proportions
(between 0.1 and 40 percent by weight) of multi-walled carbon nanotubes in the
polymethylmethacrylate (PMMA) matrix. Researchers used SEM (scanning electron
microscope) micrographs and conductivity tests to demonstrate the formation of a
conductive nanotube network in the polymer matrix. An increase in DC conductivity was
observed as the nanotube percent by weight increased. Concurrent measurements of
electromagnetic shielding efficiency showed that the SE (Shielding Efficiency) value for a
40% nanutube content gives a maximum value of 27 dB, giving rise to possible
applications in the far field range (above 10 MHz). Because of the moderate conductivity
of the nanocomposite, the absorption portion of the total SE value is larger than the
reflection portion, giving rise to extremely promising application possibilities for shield
coating in the microwave/radiowave frequency range for military purposes and for
telecommunications. The main intended initial areas of use for this flexible, costeffective,
and mass production-capable shielding material are mobile electrical devices
and equipment.
3.5 Conclusions
There is a wide range of research, application and security related product examples that
prove the important enabling role of nanotechnology for the development of future
personal protection and decontamination technologies. In view of new threats and the
growing demand for improved civil security technologies, it can be anticipated that the
ongoing progress in the development of security filter applications and the
implementation of robust and multi-usable decontamination technologies in particular will
be dominated in the mid-term by the controlled design and use of nanostructured
materials and coatings. Nanoscience and nanostructures will enable revolutionary
advances in adsorbent materials, separation technologies, neutralization/decontamination
of agents, and prophylactic measures. The main research targets in this field are related
to the:
development of smart nanoparticles or tuneable photocatalysts that recognize and
sequester or destroy specific toxins;
smart and designed nanostructured membranes with controlled porosity for
selective migration and separation;
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