A Superior Method for Constructing Electrical Percolation Network of Nanocomposite Fibers: In Situ Thermally Reduced Silver Nanoparticles

Abstract

Nanocomposite fibers, composed of conductive nanoparticles and polymer matrix, are crucial for wearable electronics. However, the nanoparticle mixing approach results in aggregation and dispersion problems. A revolutionary synthesis method by premixing silver precursor ions (silver ammonium acetate) with polyvinyl alcohol is reported here. The solvation of ions‐prevented aggregation, and uniformly distributed silver nanoparticles (in situ AgNPs, 77 nm) are formed after thermal reduction (155 °C) without using additional reducing or dispersion agents. The conductive fiber is synthesized by the wet spinning technology. After careful optimization, flower‐shaped silver nanoparticles (AgNFs, 350–450 nm) are also employed as cofillers. The addition of in situ AgNPs (9.5 vol%) to AgNFs (30 vol%) increases electrical conductivity by 1434% (2090 to 32 064 S cm−1) through the efficient construction of percolation networks. The in situ AgNPs provide significantly higher conductivity compared with other secondary nanoparticle fillers. The gaseous byproducts dramatically increase flexibility with a moderate compromise in tensile strength (55 MPa). The particle‐free ion‐level uniform mixing of silver precursors, followed by in situ reduction, would be a fundamental paradigm shift in nanocomposite synthesis.

Electron tunneling of hierarchically structured silver nanosatellite particles for highly conductive healable nanocomposites

“…The stretching cycle durability and/or healing efficiency were limited in previous reports, without additional encapsulation layer, increasing resistance with repeated cycles 2,12 . This work was also different from our previous report where the solvated Ag ions were directly mixed with the polymer solution 38 . There was no Ag ion diffusion or etching process 38 .…”

“…This work was also different from our previous report where the solvated Ag ions were directly mixed with the polymer solution 38 . There was no Ag ion diffusion or etching process 38 . The solvated Ag ions were then thermally reduced into AgNPs 38 .…”

“…5g). The σ of the typical fillerpolymer matrix nanocomposites in literature also increased after thermal curing process 2,23,38,43 . However, the σ dramatically decreased to 8.48 × 10 −3 S cm −1 after the first breaking/healing cycle due to the fracture of coalesced AgNFs (Fig.…”

“…There was no Ag ion diffusion or etching process 38 . The solvated Ag ions were then thermally reduced into AgNPs 38 .…”

NMR as a Tool to Characterize the Aggregation Structure of Silica Nanoparticles in a Liquid

“…Under the application of an oscillating magnetic field, the migrated nanoparticles generate a high local temperature which heals the electrical tree channels in the polymer. Ajmal et al (2019) produced that a highly-conductive silver/polyvinyl alcohol nanocomposite fibers by adding silver ions to prevent aggregation of the originally dispersed silver nanoparticles. The gaseous byproduct from the precursors dramatically increased the flexibility of the nanocomposite's tensile strength.…”