Mechanical Characterization of Polymer Nanocomposite Films: Influence of Force Regimes and Nano Silica Reinforcement

Kandemir A. Ç.

POLYMER COMPOSITES, vol.1, pp.1-14, 2025 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 1
  • Publication Date: 2025
  • Doi Number: 10.1002/pc.30072
  • Journal Name: POLYMER COMPOSITES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.1-14
  • TED University Affiliated: Yes

Abstract

This study examines the mechanical properties of biocompatible nanocomposite films composed of polyvinylpyrrolidone (PVP) reinforced with nano silica particles (NSPs), focusing on the influence of diverse force regimes. Colloidal probe microscopy (CPM) and instrumented indentation were used to assess mechanical behavior, revealing a force-dependent variation in elastic modulus. CPM measurements at microNewton-level forces yielded moduli in the MPa range, while instrumented indentation at milliNewton-level forces resulted in moduli in the GPa range, indicating a stiffer response. This variation is likely due to polymer flow behavior under different force regimes, where lower forces enhance compliance, whereas higher forces restrict material flow, increasing stiffness. Structural characterization via AFM and TEM confirmed homogeneous NSP dispersion at lower concentrations (1 and 3 wt%), while higher loadings (5 wt% and beyond) caused agglomeration and increased surface roughness. Theoretical models (Einstein, Guth, Kerner, and Mooney) underestimated reinforcement at low NSP volume fractions, suggesting that localized particle accumulation beneath the indentation tips enhances stiffness beyond model predictions. This discrepancy emphasizes the importance of real-world particle distribution and stress localization in nanocomposite films. These findings are particularly relevant for biomedical applications, where surface interactions and mechanical stability are critical.