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<p>This study systematically investigates the multifunctional performance of chitosan (CS) nanocomposites reinforced with zirconia nanoparticles (ZrO₂NPs), focusing on enhancements across structural, thermal, mechanical, optical, and dielectric properties.&#xa0;XRD-confirmed crystallinity reduction&#xa0;shows ZrO₂ NPs disrupt CS's semi-crystalline structure by breaking hydrogen-bonded networks, while introducing a dominant tetragonal phase with minor monoclinic contributions (&lt; 5%). Thermogravimetric analysis (TGA) reveals a 100&#xa0;°C increase in thermal stability (onset decomposition at 300&#xa0;°C) and doubled residual mass (35% at 800&#xa0;°C) for 15 <i>wt</i>.% ZrO₂/CS, attributed to nanoparticle-induced char reinforcement. Mechanical testing demonstrates a 330% increase in tensile strength (30 up to 130&#xa0;MPa) and improved ductility (2.5% up to 4.2% strain) at 5 <i>wt</i>.% loading—outperforming TiO₂-reinforced CS. Optically, tunable bandgap narrowing (5.4–2.9&#xa0;eV) enables UV shielding (20% transmittance at 15 <i>wt</i>.%) while preserving visible-light transparency. Dielectric analysis via the Havriliak-Negami (HN) framework reveals composition-dependent behavior: maximum dielectric constant (<i>ε</i>′ ≈ 280 at 360&#xa0;K) occurs at 15 <i>wt</i>.% due to enhanced Maxwell–Wagner-Sillars polarization, while&#xa0;20 <i>wt</i>.% loading causes agglomeration-induced saturation of dielectric loss. AC conductivity follows the universal power law, increasing with frequency/temperature. Crucially,&#xa0;<i>DC</i> conductivity peaks at 10 <i>wt</i>.% (5.1 × 10⁻⁷ S/m at 320&#xa0;K), indicating optimal percolative network formation,&#xa0;then plummets to 8.0 × 10⁻⁸ S/m at 20 <i>wt</i>.% due to agglomeration-disrupted pathways. The reduction in activation energy (from 0.41 to 0.26&#xa0;eV) confirms enhanced charge mobility, although microstructural limitations become dominant beyond 10 <i>wt</i>.%. These synergistic improvements—arising from ZrO₂’s interfacial interactions, quantum confinement, and structural reinforcement—underscore the nanocomposites’ promise for biomedical scaffolds, UV-protective coatings, and flexible electronic applications.</p> Graphical Abstract <p></p>

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Developing multifunctional chitosan nanocomposites with zirconia: structural, thermal, mechanical, optical, and dielectric properties enhancements

  • 期刊论文

  • 发表日期：

    2025年8月18日

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  • Emad M. Ahmed

摘要

This study systematically investigates the multifunctional performance of chitosan (CS) nanocomposites reinforced with zirconia nanoparticles (ZrO₂NPs), focusing on enhancements across structural, thermal, mechanical, optical, and dielectric properties. XRD-confirmed crystallinity reduction shows ZrO₂ NPs disrupt CS's semi-crystalline structure by breaking hydrogen-bonded networks, while introducing a dominant tetragonal phase with minor monoclinic contributions (< 5%). Thermogravimetric analysis (TGA) reveals a 100 °C increase in thermal stability (onset decomposition at 300 °C) and doubled residual mass (35% at 800 °C) for 15 wt.% ZrO₂/CS, attributed to nanoparticle-induced char reinforcement. Mechanical testing demonstrates a 330% increase in tensile strength (30 up to 130 MPa) and improved ductility (2.5% up to 4.2% strain) at 5 wt.% loading—outperforming TiO₂-reinforced CS. Optically, tunable bandgap narrowing (5.4–2.9 eV) enables UV shielding (20% transmittance at 15 wt.%) while preserving visible-light transparency. Dielectric analysis via the Havriliak-Negami (HN) framework reveals composition-dependent behavior: maximum dielectric constant (ε′ ≈ 280 at 360 K) occurs at 15 wt.% due to enhanced Maxwell–Wagner-Sillars polarization, while 20 wt.% loading causes agglomeration-induced saturation of dielectric loss. AC conductivity follows the universal power law, increasing with frequency/temperature. Crucially, DC conductivity peaks at 10 wt.% (5.1 × 10⁻⁷ S/m at 320 K), indicating optimal percolative network formation, then plummets to 8.0 × 10⁻⁸ S/m at 20 wt.% due to agglomeration-disrupted pathways. The reduction in activation energy (from 0.41 to 0.26 eV) confirms enhanced charge mobility, although microstructural limitations become dominant beyond 10 wt.%. These synergistic improvements—arising from ZrO₂’s interfacial interactions, quantum confinement, and structural reinforcement—underscore the nanocomposites’ promise for biomedical scaffolds, UV-protective coatings, and flexible electronic applications.

Graphical Abstract