Excluded-volume corrections to the single-chain static properties of a polymer melt: Temperature, density and potential effects

Excluded-volume effects on single-chain statics are introduced by analytic corrections to the Rouse results. The final expressions do not depend on free parameters. They are compared with numerical simulations of a polymer melt for different values of the temperature, the density and the interaction potential. Density and interactions control the energy landscape of the system, whereas the temperature selects the accessible regions. The agreement between the theory and the Rouse modes does not depend markedly on the temperature with some improvement for the first modes (large length scales). Differently, increasing the packing and the stiffness of the monomer-monomer interaction reduces the deviations for the first modes, but it leaves the magnitude of the deviations for the high-indexes modes (short length scales) nearly unaffected or with some tendency to increase. The scaling properties of the corrections are briefly discussed. (C) 2007 Elsevier B.V. All rights reserved.