Phase -behavior and diffusion in polymer-grafted nanoparticle films

Polymer nanocomposites (PNCs) are interesting systems for study for their tunable and enhanced properties, from optoelectronics to dielectric materials to gas separation membranes. These properties are tunable via control over the composition, morphology, and mobility of the polymer and nanoparticles in the PNC. Polymer-grafted nanoparticles (PGNPs) show a high degree of dispersion in this regard, and we study their phase behavior and diffusion in dissimilar PGNPs thin films. We apply time-of-flight secondary ion mass spectroscopy (ToF-SIMS) to measure phase behavior in thermally annealed PSAN-SiO2/PMMA-SiO2 blend films as a function of depth and scanned by AFM. Tof-SIMS was also used to measure interdiffusion in bilayer samples of PMMA-SiO2 and organo-nanoparticle (oNP) of inimer B and a crosslinker E (EDGMA). These experiments are carried out for different organo-nanoparticles with variations of inimar B (90-60%) and cross-linker E (10-40%) for different annealing times above their glass transition temperature. Diffusion coefficients are calculated by fitting the data to Fick's equation of diffusion. These samples are compared to X-ray reflectivity (XRR) and neutron reflectivity (NR) measurements.