THE THETA-POINT AND CRITICAL-POINT OF SELF-AVOIDING WALKS - A PHENOMENOLOGICAL APPROACH

Considering that the reference state of a polymer chain is the self-avoiding walk and not the Brownian walk, we propose modified forms of the Flory and Flory-Huggins models. All our results for the theta-point of a chain and for the critical point of a suspension are based on the number of contacts and the number of configurations of a chain in a good solvent. Results for d = 3 fit remarquably well with experiment (in particular we find a critical volume fraction phi(c) approximately N-0.382). For d = 2, the results concerning the critical point seem to be correct but the theta-point does not coincide with the Duplantier-Saleur result.