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|Title: ||Perfluoropolyethers: Development of an All-Atom Force Field for Molecular Simulations and Validation with New Experimental Vapor Pressures and Liquid Densities|
|Authors: ||Black, Jana E.|
Silva, Gonçalo M. C.
Iacovella, Christopher R.
Martins, Luís F. G.
Filipe, Eduardo J. M.
|Issue Date: ||May-2017|
|Publisher: ||ACS Publications|
|Citation: ||Jana E. Black, Goncalo M. C. Silva, Christoph Klein, Christopher R. Iacovella, Pedro Morgado, Luís F. G. Martins, Eduardo J. M. Filipe, Clare McCabe, J. Phys. Chem. B, 2017, 121, 6588−6600|
|Abstract: ||A force field for perfluoropolyethers (PFPEs) based on the
general optimized potentials for liquid simulations all-atom (OPLS-AA) force
field has been derived in conjunction with experiments and ab initio quantum
mechanical calculations. Vapor pressures and densities of two liquid PFPEs,
perfluorodiglyme (CF3−O−(CF2−CF2−O)2−CF3) and perfluorotriglyme
(CF3−O−(CF2−CF2−O)3−CF3), have been measured experimentally to
validate the force field and increase our understanding of the physical
properties of PFPEs. Force field parameters build upon those for related
molecules (e.g., ethers and perfluoroalkanes) in the OPLS-AA force field, with
new parameters introduced for interactions specific to PFPEs. Molecular
dynamics simulations using the new force field demonstrate excellent
agreement with ab initio calculations at the RHF/6-31G* level for gas-phase
torsional energies (<0.5 kcal mol−1 error) and molecular structures for several
PFPEs, and also accurately reproduce experimentally determined densities (<0.02 g cm−3 error) and enthalpies of vaporization
derived from experimental vapor pressures (<0.3 kcal mol−1). Additional comparisons between experiment and simulation show
that polyethers demonstrate a significant decrease in enthalpy of vaporization upon fluorination unlike related molecules (e.g.,
alkanes and alcohols). Simulation suggests this phenomenon is a result of reduced cohesion in liquid PFPEs due to a reduction in
localized associations between backbone oxygen atoms and neighboring molecules.|
|Appears in Collections:||CQE - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica|
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