Block Copolymers with Gold Nanoparticles: Correlation between Structural Characteristics and Mechanical Properties

We developed a strategy to generate gold nanoparticles within the P4VP domains of a PS-b-P4VP diblock copolymer in solid state. An organic−inorganic lamellar structure was obtained through selective incorporation of a gold precursor to the pyridine groups in the P4VP block. Understanding how nanoparticles can affect the linear viscoelastic behavior of a block-copolymer system, could assist in defining a specific processing window for this type of hybrid materials. Herein we compared the rheology of BCPs with and without nanoparticles in order to correlate structure to macroscopic response under mechanical shear. We found that nanoparticles affect significantly the glass transition temperature (T g) of the P4VP block in which these are sequestered, but also T ODT of the block copolymer system. After reduction and shear alignment, a homogeneous spatial distribution of metallic gold nanoparticles is found within the P4VP phase. These findings are confirmed with scattering methods and transmission electron microscopy measurements. Finally, electric force microscopy scans on the surface of these materials revealed dielectric contrast between the two domains of the hybrid lamellar structure.