Ag Nanoparticle-Thiolated Chitosan Composite Coating Reinforced by Ag-S Covalent Bonds with Excellent Electromagnetic Interference Shielding and Joule Heating Performances

Conductivecomposite coatings are an important element in flexibleelectronics research and are widely used in energy transformation,artificial intelligence, and electronic skins. However, the comparativelylow electrical conductivity limits their performance in many specificapplications, such as electromagnetic interference (EMI) shieldingand Joule heating devices. Therefore, the preparation of ultrahigh-electricalconductivity composite coatings with good flexibility and durabilityremains a great challenge. Herein, we fabricated multifunctional conductivecomposite coatings based on thiolated chitosan (TCS) and Ag nanoparticles(AgNPs) by an eco-friendly drop-coating method. The three-dimensionalconductive network constructed by thermal sintering imparted the coatingwith an ultrahigh electrical conductivity of up to 67079.4 S/m. Moreover,the coating reinforced by Ag-S covalent bonding exhibits goodstability, including heat resistance, chemical resistance, and mechanicalstability. In addition, based on the ultrahigh electrical conductivity,the coating exhibits superior EMI shielding effectiveness and Jouleheating capability. With 30 wt % of AgNPs in the coating, the EMIshielding effectiveness of the coating reaches 70.2 dB, far exceedingcommercial standards. Additionally, the coating can quickly reacha saturation temperature (T (s)) of 195.9 degrees C at a safe drive voltage of 3 V. These excellent performancesdemonstrate that the robust and flexible highly conductive compositecoatings prepared by this method have attractive potential for EMIshielding and thermal management applications as well as in wearableelectronics.

Automated summary

In this study, multifunctional conductive composite coatings based on thiolated chitosan and silver nanoparticles were fabricated using an eco-friendly drop-coating method. The coating achieved an ultrahigh electrical conductivity of up to 67079.4 S/m through the construction of a three-dimensional conductive network by thermal sintering. Additionally, the coating exhibited excellent stability and showed superior EMI shielding effectiveness and Joule heating capability.