Scholarlink

<p>In this work, silver nanoparticles (AgNPs) were synthesized via a green route using <i>Tilia</i> extract as a dual reducing and stabilizing agent and incorporated into chitosan (Cs)–polyvinyl alcohol (PVA) nanocomposite films via ex-situ and in-situ methods to compare incorporation pathways. UV–Vis spectroscopy enabled optimization of synthesis parameters, identifying optimal conditions of a 2/8 ratio, 70&#xa0;°C, pH 11, and 8 × 10⁻<sup>3</sup>&#xa0;mol&#xa0;L⁻<sup>1</sup>, which yielded a strong SPR peak at ~ 439&#xa0;nm, confirming controlled nanoparticle formation. XRD confirmed highly crystalline FCC Ag⁰ with an average crystallite size of ~ 32&#xa0;nm, while TEM showed spherical particles (~ 20–30&#xa0;nm). DLS and zeta potential (−&#xa0;24.5&#xa0;mV) indicated good colloidal stability. FTIR and SEM analyses revealed stronger polymer–Ag interactions and more uniform nanoparticle dispersion in in-situ nanocomposites compared to ex-situ ones. DSC confirmed blend miscibility and enhanced thermal stability upon AgNP incorporation<b>.</b> Swelling studies showed that AgNP loading increased water uptake in PVA-rich matrices, reaching up to ~ 4400%, while in-situ systems exhibited near-zero swelling due to network densification. Additionally, pronounced pH-responsive swelling under acidic conditions highlights their suitability for biomedical applications<b>.</b> Dielectric analysis revealed <i>a</i> &gt; 20-fold increase in dielectric constant (6.02 to ~ 120 at 100&#xa0;Hz) with enhanced conductivity, along with the presence of non-Debye relaxation behavior<b>.</b> Optically, AgNP incorporation induced SPR absorption (420–450&#xa0;nm), reduced the band gap (5.3–3.0&#xa0;eV), and increased optical conductivity, while also reducing transparency and refractive index, indicating enhanced structural disorder and improved charge-transfer characteristics. These findings clarify the structure–property relationships of green AgNP/Cs–PVA nanocomposites and highlight their potential for flexible optoelectronic and energy-related devices.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Eco-synthesized AgNP/Chitosan–PVA nanocomposite films: pH-responsive optical and dielectric properties for flexible optoelectronic devices

  • 期刊论文

  • 发表日期：

    2026年5月25日

查看全文
  • Chaibi Wahiba,
  • Mohammed Beldjilali,
  • S. El-Gamal,
  • Gh. Mohammed

摘要

In this work, silver nanoparticles (AgNPs) were synthesized via a green route using Tilia extract as a dual reducing and stabilizing agent and incorporated into chitosan (Cs)–polyvinyl alcohol (PVA) nanocomposite films via ex-situ and in-situ methods to compare incorporation pathways. UV–Vis spectroscopy enabled optimization of synthesis parameters, identifying optimal conditions of a 2/8 ratio, 70 °C, pH 11, and 8 × 10⁻3 mol L⁻1, which yielded a strong SPR peak at ~ 439 nm, confirming controlled nanoparticle formation. XRD confirmed highly crystalline FCC Ag⁰ with an average crystallite size of ~ 32 nm, while TEM showed spherical particles (~ 20–30 nm). DLS and zeta potential (− 24.5 mV) indicated good colloidal stability. FTIR and SEM analyses revealed stronger polymer–Ag interactions and more uniform nanoparticle dispersion in in-situ nanocomposites compared to ex-situ ones. DSC confirmed blend miscibility and enhanced thermal stability upon AgNP incorporation. Swelling studies showed that AgNP loading increased water uptake in PVA-rich matrices, reaching up to ~ 4400%, while in-situ systems exhibited near-zero swelling due to network densification. Additionally, pronounced pH-responsive swelling under acidic conditions highlights their suitability for biomedical applications. Dielectric analysis revealed a > 20-fold increase in dielectric constant (6.02 to ~ 120 at 100 Hz) with enhanced conductivity, along with the presence of non-Debye relaxation behavior. Optically, AgNP incorporation induced SPR absorption (420–450 nm), reduced the band gap (5.3–3.0 eV), and increased optical conductivity, while also reducing transparency and refractive index, indicating enhanced structural disorder and improved charge-transfer characteristics. These findings clarify the structure–property relationships of green AgNP/Cs–PVA nanocomposites and highlight their potential for flexible optoelectronic and energy-related devices.