CNT-Grafted AgNP/AgNW Embedded in Sodium Alginate-PVA Films for EMI Shielding and Electrical Heating

Electromagnetic waves endanger precision instruments and human health, driving the demand for multifunctional flexible transparent conductive films (FTCFs) with integrated electromagnetic interference (EMI) shielding and electric heating to ensure reliable microelectronic performance in extreme environments beyond conventional materials’ limits. However, current FTCFs based on carbon nanomaterials, metal nanowires, or 2D materials still suffer from insufficient oxidation resistance, weak adhesion to substrates, and performance degradation under complex conditions, limiting their practical deployment. To address these, we designed the films, which involved constructing silver nanowire/carbon nanotubes/silver nanoparticle (AgNW/CNT@Ag) conductive networks on polyethylene terephthalate (PET) via spray and spin coating, followed by transferring them into glycerol-modified, sodium alginate (SA)-poly(vinyl alcohol) (PVA) composite layers. This structure leverages AgNPs grafted on CNTs, forming resistor-capacitor-like configurations to enhance EMI shielding via improved electromagnetic wave absorption. The embedded design, combined with CNT coverage over AgNW, strengthens the adhesion and oxidation resistance by blocking oxygen. Additionally, SA-induced surface wrinkles boost conductivity and wave reflection, while the conductive network enables efficient Joule heating. The resulting film exhibits performance: 9.46 Ω/sq sheet resistance @ 57.7% transmittance, a figure-of-merit (FoM) of 6.31, an EMI shielding effectiveness of 31.42 dB, a saturation temperature of 93.1 °C at 6 V, a relative resistance change (RRC) of 0.92 after 60 oxidation cycles, and an RRC of 0.36 after 1000 bending cycles. This work provides a promising structural design and material strategy for FTCFs, advancing their commercialization in multifunctional electronic applications.