Studies on the electromagnetic interference shielding effectiveness of metallized PVAc-AgNO3/PET conductive films

摘要

A metal chelate polymer (MCP) of PVAcAgNO3 was prepared by adding AgNO3 salts into the PVAc matrix and was coated on to PET substrate to form PVAcAgNO3/PET films. These films were then treated with NaBH4 aqueous solution to become the reduced metallized conductive films (RMCF) of PVAc-AgNO3/PET. The electromagnetic interference shielding effectiveness (EMI/SE) and the characteristics of these films were investigated. The SE value was measured by the far-field transmission line method. The surface resistivity (Rs) of RMCF with a AgNO3 content of 15 wt% was found to be below 5 Omega/sq, and the SE value exceeded 20 dB over the frequency range 50-900 MHz. The Rs of RMCF with a AgNO3 content of 30 wt% was less than 1 Omega/sq, and the SE value even reached 33 dB at 550-650 MHz. It was confirmed by X-ray and scanning electronmicroscope (SEM) analysis that the conducting network, as formed by closely deposited silver atoms on the reduced coating surface, was the dominant pathway for effective electron propagation that contributed to the excellent conductivity of these RMCF (PVAc-AgNO3/PET). (C) 2003 Wiley Periodicals, Inc. [References: 14]