Frequency selective absorbing property of nanoring-shaped polyaniline with broadband absorption

Frequency selective absorbing property (FSAP) is a key to realize radar frequency selective surfaces' stealth technology, which has great application prospects in national military industry. Different from traditional metal materials, herein, through the design of polyaniline microstructure as well as doping modification of the polymerization, polyaniline nanorings (PANI NRs) with certain electrical conductivity have been constructed. By constructing nanoring-shaped morphology, PANI NRs achieve strong reflection and great absorption of electromagnetic waves (EMWs) in different frequency ranges. These two properties are vital for realizing high-efficient FSAP. PANI NRs demonstrate negative permittivity within 50–1000 MHz frequency range where they can show strong EMWs reflection, and the negative permittivity is attributed to the plasma-like behavior of conductive network formed by plenty of overlapping nanorings. In addition, this porous structure also contributes to increase reflection and refraction of incident EMWs and then continuously consuming their energy, ensuring outstanding EMWs absorption property during 2–18 GHz frequency bandwidth.