Accurate excluded-volume corrections to the single-chain static properties of a melt of unentangled polymers

Actual polymer chains cannot cross themselves and each other. However, the popular Rouse model for unentangled polymers considers the chains as being like 'phantoms'. It is shown that excluded volume effects on single-chain statics may be introduced by analytic corrections to the Rouse results. The final expressions do not depend on free parameters. They exhibit excellent agreement with the molecular-dynamics simulations of polymer melts with chain lengths in the range 3 <= M <= 30. Preliminary results for entangled polymer melts are presented.