title: Density functional theory for inhomogeneous ring polymeric fluids.
abstract: The modeling of ring polymers remains a challenge in classical density functional theory (DFT) due to the difficulty in solving the direct bond connectivity of the ring architecture without free ends. By considering the feature that all of the segments in a ring are equivalent, we give an algorithm to solve the integral of direct bond connectivity for ideal ring polymers, and therefore propose a DFT for inhomogeneous ring polymers, where the excess free energy functional is extended from an equation of state (EOS). This EOS exhibits better agreement than other EOSs for the compressibility factors, compared to Monte Carlo data. Importantly, the DFT satisfactorily reproduces the data of the configurational-bias Monte Carlo (CBMC) simulations for ring polymers. The local density profiles from the DFT show that the bead density of inhomogeneous ring fluids is independent of ring size, which is also confirmed by the CBMC simulations. Interestingly, the behavior of solvation force for ring polymers is quite similar to that of the polymers with infinite chain length.
authors.affiliation: Division of Molecular and Materials Simulation, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Jiang
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Xu
authors.forename: Dapeng
authors.initials: D
authors.lastname: Cao
mesh_terms: D000465:Algorithms; D001703:Biophysics / Q000379:methods*; D003198:Computer Simulation; D019281:Dimerization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D009010:Monte Carlo Method; D020959:Polyethylene / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D011108:Polymers; D011137:Polystyrenes; D020959:Polyethylene