Fabrication of Mono- and Multilayered Large-Area Ultrathin Polymer Nanocomposite Films: Implications for Functional Nanoparticle Applications

Ultrathin polymer nanocomposite films are gaining importance in electronic, optical, magnetic, or sensor devices with widespread applications in the areas of electronics, information technology, and medicine. Future developments in ultrathin nanocomposite films require the fabrication of ever thinner films with controllable thickness, homogeneous nanoparticle distribution, and large areas. We here demonstrate a dip-coating-delamination method to prepare ultrathin and large-area polymer nanocomposite films on various substrates or as free-standing films. We demonstrate thickness control in the range between 17 and 150 nm, controlled via film withdrawing speed and nanoparticle volume fraction. Ultrathin films with magnetic, semiconductor, and down-conversion nanoparticles having spherical, rod-like, or platelet shapes can be prepared. We show that the magnetic and optical properties of the nanoparticles are well preserved by the fabrication method. Furthermore, we demonstrate the assembly of ultrathin large-area hetero multilayer nanocomposite films. This method thus provides a versatile, well-controllable, and scalable method to prepare supported or free-standing multifunctional large-area ultrathin nanocomposite films with low material consumption.