Temperature-Driven Grafted Nanoparticle Penetration into Polymer Melt: Role of Enthalpic and Entropic Interactions.*

Polymer grafted nanoparticles (PGNPs) based ultra-thin membranes are coupled to some substrates, the role of membrane–substrate interactions, nanoparticle (NP) penetration into soft matter systems are indispensable for numerous applications ranging from targeted nanoparticle-based drug delivery to generating hybrid polymer nanocomposite materials. Understanding their mechanical and thermal stability, as well as their plethora of applications. Dynamical parameters are studied using X-ray photon correlation spectroscopy, X-ray reflectivity, and the results are correlated with molecular dynamics simulations. Here we report thermal stability, membrane flexibility when the temperature of the system is below the glass transition temperature and the penetration of NP increased toward the glass transition temperature of underlying films. We report two independent pathways of PGNP penetration depending upon the enthalpic interaction between the grafted chains of PGNP monolayer (top layer) and the chains of a polymer film (bottom layer) onto which the layer is transferred. The extent of PGNP penetration, membrane dynamics are improved upon increasing the entropic and enthalpic compatibility between PGNPs and the underlying bulk layer.