Fig. 1: Direct observation of the interfacial polymer around a nanoparticle in nanocomposites.

a Schematic illustration of the preparation of nanocomposite with protruded nanoparticles. t represents the thickness of the polymer film and D refers to the diameter of nanoparticle. b, c The surface (b) and cross-section (c) SEM images of the PVDF-TiO₂ nanocomposite with TiO₂ nanoparticle protruded out of the polymer matrix. The scale bar is 100 nm. d The HADDF image (up) of a TiO₂ nanoparticle embedded in the PVDF matrix, and the corresponding element mapping (middle) and line profile (blue) of carbon atom signal (bottom) near the interfacial region. The scale bar is 50 nm. e Schematic illustration of the AFM-IR measurement and the reconstructed dipole orientations in the interfacial region (left), and the interface model consisting of two interfacial polymer layers (right). f Simultaneously measured topography (left) and AFM-IR chemical maps with irradiation by a laser at 840 cm⁻¹ (middle) and 766 cm⁻¹ (right), respectively, of the interfacial region around the TiO₂ nanoparticle. The scale bar is 500 nm. g L-PFM, V-PFM phase images (up) and corresponding line profiles (bottom) showing the polarization components of the dipoles in the interface region. The scale bar is 200 nm.