Multifunctional Silver Nanowire Fabric Reinforced by Hot Pressing for Electromagnetic Interference Shielding, Electric Heating, and Sensing

Durability and multifunctionality are crucial considerations in the realm of electronic textiles. Herein, a hot-pressing process has been developed to enhance the fixation of silver nanowires (AgNWs) on polyethylene terephthalate (PET) fabric. The conductivity, electromagnetic shielding, and electric heating properties of the hot-pressed fabric were measured to demonstrate the effectiveness of the hot-pressing process. The conductivity of the hot-pressed fabric (180 °C for 90 s) was found to be 464.2 S/m, while that of the fabric without hot pressing was 94.9 S/m. The washed hot-pressed fabric was able to provide a maximum electromagnetic shielding of 17 dB, a negative strain sensing performance (the ΔR/R0 of the hot-pressed fabric was maintained at -15%), and an outstanding electric heating property (the temperature reached 110 °C at a current of 0.08 A). This AgNW fabric holds great potential for use in multi-functional wearable devices, and the hot-pressing process improved its stability and durability, making it suitable for industrial production.

Silver Ions Drive Ordered Self-Assembly Mechanisms and Inherent Properties of Lignin Nanoflowers

Designing anisotropic lignin-based particles and promoting the high-value utilization of lignin have nowadays drawn much attention from scientists. However, systematic studies addressing the self-assembly mechanisms of anisotropic lignin-based particles are scarce. In this work, an interaction including the electrostatic forces and chelating forces between lignin and Ag+ was regulated via carboxymethylation modification. Subsequently, the aggregation morphology of carboxymethylated lignin in a Ag+ solution was observed via SEM. The result showed that a large number of Ag+ intercalated into the lignin molecules when the grafting degree of the carboxyl groups increased from 0.17 mmol/g to 0.53 mmol/g, which caused the lignin molecules to gradually transform from disordered blocks to ordered layers. Dynamics research indicated that the adsorption process of Ag+ in carboxymethylated lignin conforms to the Pseudo-first-order kinetic model. The saturated adsorption amount of Ag+ in the carboxymethylated lignin reached 1981.7 mg/g when the grafting rate of carboxyl groups increased to 0.53 mmol/g, which then fully intercalated into lignin molecules and formed a layered structure. The thermodynamic parameters showed that the thermal adsorption process conforms to the Langmuir model, which indicates that Ag+ is monolayer-adsorbed and intercalated into lignin molecules. Meanwhile, the ΔH values are more than 0, which suggests that this adsorption process is a endothermic reaction and that a higher temperature is conducive to an adsorption reaction. Therefore, self-assembly of lignin in a Ag+ solution under 70 °C is more conducive to the formation of a nanoflower structure, which is consistent with our experimental result. Finally, pH-responsive Pickering emulsions were successfully prepared using a lignin-based nanoflowers, which demonstrated their potential as a catalytic platform in the interface catalysis field. This work offers a deeper understanding into the formation mechanism of anisotropic lignin-based nanoflowers and hopes to be helpful for designing and preparing anisotropic lignin-based particles.