The influence of solvent on the static properties of polymer chains in solution: A molecular dynamics simulation

The conformational properties of flexible polymer chains in dilute and concentrated solutions have been studied by computer simulation using the molecular dynamics technique. The polymer itself is represented by a freely linked chain consisting of 16 beads and the low-molecular solvent by the same particles as the chain beads. Equilibrium properties of the chain such as the end-to-end distance, the radius of gyration and the average bond angle are computed. All these quantities are compared with those obtained for an isolated chain without solvent particles. We conclude that within the accuracy of our calculation the behaviour of the chain immersed in a monomeric solvent is mainly determined by intrachain interactions rather than by solvent effects, i.e. the solvent has almost no effect on the static structure of the chain. Studies of multiple chain systems at a density of 0·8 demonstrate that both the local chain conformation and chain dimensions are very similar to those expected for an ideal gaussian chain. The influence of attractive forces on the static properties is also investigated and a qualitative comparison of present results with those of other authors is made.