Investigation on the preparation of silver coated carbon nanotubes (SCCNT) and SCCNT/polyacrylate composite coatings for electromagnetic interference shielding

摘要

The increasing use of electronic divices has caused the problem of electromagnetic interference (EMI). Silver coated carbon nanotubes (SCCNT) is a good candidate for EMI shielding due to its combining the excellent properties of silver (Ag) and carbon nanotubes. A noval method to prepare SCCNT was demonstrated that multi-walled carbon nanotubes (MWCNTs) were applied to electroless nickel-phosphorus (Ni-P) deposition, followed by electroless Ag plating. The microstructure and morphology of as-prepared SCCNT were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results showed that the Ag coating on MWCNTs was continuous and compact. SCCNT/polyacrylate composite coatings were fabricated and the volume resistivity were measured through the current-voltage (I-V) characteristics of the composite. The effects of the pretreatment of MWCNTs and the concentration of composition in electroless plating bath on the resistivity of SCCNT composite were studied. Then the optimum formula and process were concluded. The as-prepared SCCNT/polyacrylate composite coatings with the minimum resistivity of 1.1 mΩ·cm exhibited a high EMI shielding effectiveness (SE) of more than 46.5 dB in the frequency range from 3.95 to 5.85 GHz with the maximum value of 53.25 dB at 4.05 GHz.