Conductive polymer composites (CPCs) containing nanoscale conductive fillers have been widely studied for their potential use in various applications. In this paper, polypyrrole (PPy)/polydopamine (PDA)/silver nanowire (AgNW) composites with high electromagnetic interference (EMI) shielding performance, good adhesion ability and light weight are successfully fabricated via a simple in situ polymerization method followed by a mixture process. Benefiting from the intrinsic adhesion properties of PDA, the adhesion ability and mechanical properties of the PPy/PDA/AgNW composites are significantly improved. The incorporation of AgNWs endows the functionalized PPy with tunable electrical conductivity and enhanced EMI shielding effectiveness (SE). By adjusting the AgNW loading degree in the PPy/PDA/AgNW composites from 0 to 50 wt%, the electrical conductivity of the composites greatly increases from 0.01 to 1206.72 S cm⁻¹, and the EMI SE of the composites changes from 6.5 to 48.4 dB accordingly (8.0–12.0 GHz, X-band). Moreover, due to the extremely low density of PPy, the PPy/PDA/AgNW (20 wt%) composites show a superior light weight of 0.28 g cm⁻³. In general, it can be concluded that the PPy/PDA/AgNW composites with tunable electrical conductivity, good adhesion properties and light weight can be used as excellent EMI shielding materials.

A convenient and low-cost approach to fabricate a high-quality copper layer on epoxy resin via electroless plating for applications in electromagnetic interference (EMI) shielding is introduced in this paper. Through the surface modification of thiosulfate (S₂O₃ ²⁻), an epoxy resin substrate is able to adsorb silver ions, which could create a catalytic activating layer to catalyze the subsequent electroless copper plating (ECP) of a conductive deposited copper layer at low temperature. The effects of thiosulfate are evaluated based on water contact angle measurement, XPS, FT-IR, SEM, EDS and adhesion tests. The incorporation of thiosulfate effectively modifies the epoxy resin substrate surface, thus promoting adhesion between the epoxy resin and the deposited copper layer. Moreover, after 40 min of ECP, the resulting deposited copper layer presents a low resistivity of 2.24 × 10⁻⁶ Ω cm and an excellent electromagnetic interference shielding effectiveness of greater than 60 dB in the frequency range from 4 GHz to 18 GHz. It can be concluded that the developed technology can be used to enable surface metallization of epoxy resin as a highly effective electromagnetic interference shielding material without the use of high temperatures or sophisticated manufacturing equipment.