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Efficient shielding materials are extremely important to minimize the effect of electromagnetic interference. Currently, various composite materials are being investigated with different shielding efficiencies reported. In this paper, a flexible and free-standing sodium-based chitosan (CH/Na) polymer with copper selenide (CuSe) filler was prepared for electromagnetic shielding. The CH/Na/CuSe polymer matrix was prepared via the direct casting technique at different wt% of CuSe, varying from 2 to 20 wt%. The polymer matrix was then characterised by using Fourier transform infrared (FTIR) spectroscopy to confirm the interaction between the CH/Na and CuSe. The XRD results revealed that the CH/Na/CuSe polymer was successfully formed. Improvement in the electrical conductivity was confirmed by an impedance spectroscopy measurement. The highest electrical conduction recorded was at 3.69 × 10−5 S/cm for CH/Na/CuSe polymer matrix with 20 wt% CuSe. An increase in total electromagnetic interference (EMI) shielding efficiency (SET) of up to 20 dB (99% EM power shield) was achieved, and it can be increased up to 34 dB (99.9% EM power shield) with the thickness of the polymer increased.

This paper reports on chitosan/bentonite crosslinked (ChB-ECH) film for removal of Cu (II). The effects of chitosan/bentonite ratio on the removal percentage were studied along with the effect of different Cu (II) concentration and the contact time on the film adsorption capacity, qt. The electrical properties of the film are studied, before and after the adsorption occurred, by using impedance spectroscopy for different parameters such as DC conductivity, the complex dielectric constants (ε′ and ε″) and complex electrical modulas (M′ and M″). The results showed that the chitosan/bentonite ratio of 3:1 produces highest removal percentage at 29%, while the contact time of 120 minutes was found to be optimum. An increment in the DC conductivity of the ChB-ECH film's was observed up to 10−7 S/cm as the removal percentage of film increased. The film with the highest Cu (II) adsorb also showed the highest value for ε′ and ε″ while exhibiting non-Derby behavior. Shifting of peak amplitude of the M″ towards the higher frequency was also observed as the Cu (II) adsorption in the film increased. The results showed that all the electrical parameters can be utilized to determine the amount of adsorbed copper (II) in chitosan/bentonite film.