M. McTaggart, C. Malardier-Jugroot
Royal Military College of Canada,
Keywords: nanoreactors, nanocomposites, catalysis, self-assembly, molecular simulation
Summary:We have developed and thoroughly characterized stable polymer-metal nanocomposite reactor systems with hydrophobic inner surfaces 2-3 nm apart. Previous work has shown that energetically unfavourable reactions, namely pyrrole polymerization and metal salt reduction, spontaneously occur under confinement within the polymer nanostructure. Water confined in such a space enters a metastable liquid phase with solvation characteristics similar to that of supercritical water, even while the bulk solution remains at room temperature and pressure. Properties of supercritical water such as solvation free energy, compressibility, and permittivity could explain the disparity between confined and bulk thermodynamics, but it is not yet known whether this is indeed the case. The current study examines the effect of nanoconfinement on water and small solute particles.This paper presents the results of simulations using the TIP4P-Ew long-range water model developed by her lab and the LAMMPS molecular dynamics software. The statistical data collected demonstrates the thermodynamic behaviour of confined water, including its solvation energy for various small molecules such as organics, metal ions, and gases, under precisely controlled values of surface hydrophobicity and polarization. Quantum mechanical modeling by density functional theory has ensured physically accurate energies and geometry for the simulated surface topologies. The simulation results presented will be validated by comparison to experimental results of reactions under confinement within our polymer-metal nanoreactor systems.