(630a) Confinement-Induced Changes in the Dynamics of Polymers and the Toughness of Nanocomposites

Polymer-infiltrated nanoparticle films (PINFs) have exceptional mechanical, transport, and optical properties that make them highly useful in various fields, such as sensing, membrane separation, and protective coatings. These PINFs can be fabricated by heating or solvent-annealing a bilayer of polymer and nanoparticle packing which induces the infiltration of polymers into the interstices between the nanoparticles. This process not only produces functional films but also offers a unique opportunity to study the impact of extreme nanoconfinement on polymer infiltration behavior and the mechanical properties of the resulting nanocomposites. In this presentation, I will discuss our recent findings on the effects of confinement on polymer infiltration dynamics in the presence and absence of a solvent and the toughness of the nanocomposite films. I will show that the effective viscosity of polymer infiltration into the disordered nanoparticle packing can be greater or smaller than its melt state viscosity, depending on the molecular weight of the polymer and degree of confinement. The dynamics of polymer infiltration in the presence of a solvent in the pores of the nanoparticle packing exhibit a non-monotonic trend as the strength of interactions between the polymer and the nanoparticle surface is varied. I will describe an example of a functional film that are generated based on these fundamental understandings by producing broadband anti-reflection coatings with high flexibility and mechanical durability.