Autophobic Dewetting Triggered Stability of Polymer Grafted Nanoparticles in Polymer Nanocomposites

Abstract

While polymer grafting is frequently employed to improve the particle stability in polymer nanocomposites (PNCs), the chemistry of the grafting polymer needs to be the same as the matrix polymer to screen the unfavorable enthalpic interactions between particle and polymers. However, the grafted corona causes autophobic dewetting by expelling the matrix polymers from the interface when molecular weight (MW) ratio of matrix (P) to grafted (N) polymers exceeds 1. Here, we report that autophobic dewetting behavior of entangled poly(ethylene glycol) (PEG) can improve or disturb the particle dispersion stability of PNCs using a short chain PEG-grafted silica particle at P/N=21. We found that conformation change of matrix polymer significantly influences on the dispersion stability depending on the particle separation distance compared to the matrix polymer chain size, characterized by SAXS, proton time-domain NMR, and rheometry experiments.