Kinetics of functional high density polymer nanocomposite formation by tuning enthalpic and entropic barriers.

Recently various methods have been proposed to prepare high density functional polymer nanocomposites (PNCs) based on either penetration of high density nanoparticles in polymer matrix or capillary rise infiltration of polymer into a dense packing of nanoparticles. The key challenge is to attain high loading while maintaining dispersion to attain maximum possible benefit. Here, we discuss a facile method to prepare polymer grafted nanoparticle (PGNP) based high density functional polymer nanocomposites using thermal activation of a high density PGNP monolayer to overcome entropic or enthalpic barriers to insertion of PGNPs in underlying polymer films. We monitor the temperature dependent kinetics of penetration of a high density PGNP layer and correlate the penetration time to the effective enthalpic/entropic barriers. The experimental results are corroborated by coarse grained molecular dynamics simulations. Repeated application of the methodology used to insert nanoparticles by appropriate control over temperature, time and graft chain properties can lead to enhanced densities of loading in the PNC. Our method can be engineered to produce a wide range of high density PNC membranes for various possible applications including gas separation and water desalination.