We show that the variations of the surface tension of polymeric solutions $\gamma$ with the molecular weight of the sample $M_n$, the temperature $T$, and the volume fraction of monomers ${\phi }_b$ are explained by the self-organization of the long flexible chains that are present in the immediate vicinity of the interface. Within a scaling functional theory we find a simple law $\gamma ({\phi }_b{,M}_n,T)$ which accounts quantitatively for the experimental data available in the literature with a very high accuracy.

• Received 22 February 2000

DOI:https://doi.org/10.1103/PhysRevLett.84.4858