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<p>This study investigates the structural evolution and charge transport dynamics of polyvinyl chloride (PVC) nanocomposites integrated with silver tungstate α-Ag<sub>2</sub>WO<sub>4</sub>) and graphene oxide (GO) under high-dose gamma irradiation (0–150&#xa0;kGy). Flexible PVC/Ag<sub>2</sub>WO<sub>4</sub>/GO films (5.0 wt% filler loading) were synthesized via solution casting to develop radiation-tolerant materials optimized for optoelectronic and shielding applications. Field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analyses revealed a dose-dependent structural transition. Up to 100&#xa0;kGy, the system undergoes dominant radiolytic dehydrochlorination, leading to isolated polyene formation and nanorod fragmentation. Beyond 100&#xa0;kGy, a significant structural percolation threshold is reached, characterized by extensive polymer chain scission and concurrent cross-linking. This network reconfiguration forces a profound trend reversal in both thermal and optical performance. Fourier transform infrared (FTIR) spectroscopy fingerprinting confirmed that the <i>I</i><sub>C=C</sub>/<i>I</i><sub>C–Cl</sub> intensity ratio rises steadily to ~0.72. Correlative modeling using the Kissinger approach demonstrated that the thermal activation energy (<i>E</i><sub>a</sub>) drops during initial dehydrochlorination but shifts sharply upward above 100&#xa0;kGy due to the stabilizing effect of the interconnected, cross-linked network. Ultraviolet–visible (UV–Vis) spectrophotometry revealed that the direct optical bandgap (<i>E</i><sub>g</sub>) reaches a minimum of 3.65&#xa0;eV at 100&#xa0;kGy before a structural trend reversal broadens it to 3.75&#xa0;eV at 150&#xa0;kGy, validating the localized spectral masking of defects. Alternating current (AC) impedance spectroscopy confirmed that while the electronic bandgap expands at the highest dose, the continuous physical pathways formed at the percolation threshold yield an optimal, interconnected state for efficient macroscopic charge transport. These findings demonstrate that high-dose gamma irradiation can be strategically utilized to engineer specialized, stable, and conductive interconnected polymer nanocomposites.</p>

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The critical role of cross-linking: achieving optimal conductivity via percolation in PVC/Ag2WO4/GO nanocomposites under high gamma dose

  • 期刊论文

  • 发表日期：

    2026年5月29日

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  • Soad Saad Fares,
  • Dalal Alzahrani,
  • Ahmed Hassan Korna,
  • Badriah Alshahrani,
  • Hanen Hammami,
  • Noura Ben Mansour,
  • Raja Rabhi,
  • Salha Khadhraoui

摘要

This study investigates the structural evolution and charge transport dynamics of polyvinyl chloride (PVC) nanocomposites integrated with silver tungstate α-Ag2WO4) and graphene oxide (GO) under high-dose gamma irradiation (0–150 kGy). Flexible PVC/Ag2WO4/GO films (5.0 wt% filler loading) were synthesized via solution casting to develop radiation-tolerant materials optimized for optoelectronic and shielding applications. Field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analyses revealed a dose-dependent structural transition. Up to 100 kGy, the system undergoes dominant radiolytic dehydrochlorination, leading to isolated polyene formation and nanorod fragmentation. Beyond 100 kGy, a significant structural percolation threshold is reached, characterized by extensive polymer chain scission and concurrent cross-linking. This network reconfiguration forces a profound trend reversal in both thermal and optical performance. Fourier transform infrared (FTIR) spectroscopy fingerprinting confirmed that the IC=C/IC–Cl intensity ratio rises steadily to ~0.72. Correlative modeling using the Kissinger approach demonstrated that the thermal activation energy (Ea) drops during initial dehydrochlorination but shifts sharply upward above 100 kGy due to the stabilizing effect of the interconnected, cross-linked network. Ultraviolet–visible (UV–Vis) spectrophotometry revealed that the direct optical bandgap (Eg) reaches a minimum of 3.65 eV at 100 kGy before a structural trend reversal broadens it to 3.75 eV at 150 kGy, validating the localized spectral masking of defects. Alternating current (AC) impedance spectroscopy confirmed that while the electronic bandgap expands at the highest dose, the continuous physical pathways formed at the percolation threshold yield an optimal, interconnected state for efficient macroscopic charge transport. These findings demonstrate that high-dose gamma irradiation can be strategically utilized to engineer specialized, stable, and conductive interconnected polymer nanocomposites.