TY - JOUR
T1 - SAFT-γ Force Field for the Simulation of Molecular Fluids. 5. Hetero-Group Coarse-Grained Models of Linear Alkanes and the Importance of Intramolecular Interactions
AU - Rahman, Sadia
AU - Lobanova, Olga
AU - Jiménez-Serratos, Guadalupe
AU - Braga, Carlos
AU - Raptis, Vasilios
AU - Müller, Erich A.
AU - Jackson, George
AU - Avendaño, Carlos
AU - Galindo, Amparo
PY - 2018/10/4
Y1 - 2018/10/4
N2 - The SAFT-γ Mie group-contribution equation of state [ Papaioannou et al. J. Chem. Phys. 2014, 140, 054107 ] is used to develop a transferable coarse-grained (CG) force-field suitable for the molecular simulation of linear alkanes. A heterogroup model is fashioned at the resolution of three carbon atoms per bead in which different Mie (generalized Lennard-Jones) interactions are used to characterize the terminal (CH3-CH2-CH2-) and middle (-CH2-CH2-CH2-) beads. The force field is developed by combining the SAFT-γ CG top-down approach [ Avendaño et al. J. Phys. Chem. B 2011, 115, 11154 ], using experimental phase-equilibrium data for n-alkanes ranging from n-nonane to n-pentadecane to parametrize the intermolecular (nonbonded) bead-bead interactions, with a bottom-up approach relying on simulations based on the higher resolution TraPPE united-atom (UA) model [ Martin;, Siepmann J. Phys. Chem. B 1998, 102, 2569 ] to establish the intramolecular (bonded) interactions. The transferability of the SAFT-γ CG model is assessed from a detailed examination of the properties of linear alkanes ranging from n-hexane (n-C6H14) to n-octadecane (n-C18H38), including an additional evaluation of the reliability of the description for longer chains such as n-hexacontane (n-C60H122) and a prototypical linear polyethylene of moderate molecular weight (n-C900H1802). A variety of structural, thermodynamic, and transport properties are examined, including the pair distribution functions, vapor-liquid equilibria, interfacial tension, viscosity, and diffusivity. Particular focus is placed on the impact of incorporating intramolecular interactions on the accuracy, transferability, and representability of the CG model. The novel SAFT-γ CG force field is shown to provide a reliable description of the thermophysical properties of the n-alkanes, in most cases at a level comparable to the that obtained with higher resolution models.
AB - The SAFT-γ Mie group-contribution equation of state [ Papaioannou et al. J. Chem. Phys. 2014, 140, 054107 ] is used to develop a transferable coarse-grained (CG) force-field suitable for the molecular simulation of linear alkanes. A heterogroup model is fashioned at the resolution of three carbon atoms per bead in which different Mie (generalized Lennard-Jones) interactions are used to characterize the terminal (CH3-CH2-CH2-) and middle (-CH2-CH2-CH2-) beads. The force field is developed by combining the SAFT-γ CG top-down approach [ Avendaño et al. J. Phys. Chem. B 2011, 115, 11154 ], using experimental phase-equilibrium data for n-alkanes ranging from n-nonane to n-pentadecane to parametrize the intermolecular (nonbonded) bead-bead interactions, with a bottom-up approach relying on simulations based on the higher resolution TraPPE united-atom (UA) model [ Martin;, Siepmann J. Phys. Chem. B 1998, 102, 2569 ] to establish the intramolecular (bonded) interactions. The transferability of the SAFT-γ CG model is assessed from a detailed examination of the properties of linear alkanes ranging from n-hexane (n-C6H14) to n-octadecane (n-C18H38), including an additional evaluation of the reliability of the description for longer chains such as n-hexacontane (n-C60H122) and a prototypical linear polyethylene of moderate molecular weight (n-C900H1802). A variety of structural, thermodynamic, and transport properties are examined, including the pair distribution functions, vapor-liquid equilibria, interfacial tension, viscosity, and diffusivity. Particular focus is placed on the impact of incorporating intramolecular interactions on the accuracy, transferability, and representability of the CG model. The novel SAFT-γ CG force field is shown to provide a reliable description of the thermophysical properties of the n-alkanes, in most cases at a level comparable to the that obtained with higher resolution models.
UR - http://www.scopus.com/inward/record.url?scp=85054147213&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.8b04095
DO - 10.1021/acs.jpcb.8b04095
M3 - Article
C2 - 30179489
AN - SCOPUS:85054147213
SN - 1520-6106
VL - 122
SP - 9161
EP - 9177
JO - The Journal of Physical Chemistry Part B
JF - The Journal of Physical Chemistry Part B
IS - 39
ER -