Molecular dynamics studies of polyethylene oxide and polyethylene glycol: hydrodynamic radius and shape anisotropy

摘要: A revision (C35r) to the CHARMM ether force field is shown reproduce experimentally observed conformational populations of dimethoxyethane. Molecular dynamics simulations 9, 18, 27, and 36-mers polyethylene oxide (PEO) 27-mers glycol (PEG) in water based on C35r yield a persistence length λ = 3.7 A, quantitative agreement with obtained values for PEO 3.8 PEG; experimental hydrodynamic radii comparably sized PEG also excellent. The exponent υ relating radius gyration molecular weight () from equals 0.515 ± 0.023, consistent observations that low behaves as an ideal chain. shape anisotropy hydrated 2.59:1.44:1.00. dimension middle each polymers nearly diffusion measurements solution. This explains correspondence pore membrane channels: polymer such diffuses its long axis parallel channel, passes through channel without substantial distortion.