Star polymer nanocomposites with dispersed nanoparticles

Abstract

This study explores the intricate interplay between polymer topology and nanoparticle integration in the design of advanced nanocomposites, with a focus on star‐shaped poly(ethylene oxide) matrices featuring 4‐arm and 8‐arm architectures across a spectrum of arm molecular weights (1.25–5 kDa). By systematically varying nanoparticle (silica) loadings from 10 to 50 vol%, we investigate how functionality and arm length modulate microstructural organization, thermal transitions, and rheological responses. A comprehensive suite of techniques is employed, including small‐angle neutron scattering (SANS) to characterize the radius of gyration ( R g ) and conformational structure of neat star polymers, scanning electron microscopy (SEM) and small‐angle X‐ray scattering (SAXS) to assess nanoparticle dispersion uniformity across all compositions, differential scanning calorimetry (DSC) to evaluate glass transition dynamics, and small‐amplitude oscillatory shear rheology to probe viscoelastic moduli, frequency dependencies, and reinforcement mechanisms. This integrated approach illuminates how architectural parameters influence interfacial chain packing, mobility gradients, and entanglement networks, especially in high‐concentration regimes where bound layers predominate. The findings underscore the efficacy of topological design as a sophisticated means to engineer nanocomposite rheology, independent of molecular weight, nanoparticle morphology, loading, or dispersion state, offering versatile pathways for optimizing performance in viscoelastic applications such as adhesives, energy‐dissipating materials, and flexible electronics.