The mean square end-to-end distances ⟨R2⟩∝N2ν and the end-to-end vector distribution functions P(R) of a polymer chain at Θ-point and in the polymer melt are considered in the framework of the self-consistent approximation developed by Edwards. The following conclusions are drawn. i) At Θ-point 2ν=1, but P(R) is not gaussian in three dimensional space. ii) In the melt 2ν=1 and P(R) is very close to gaussian in three dimensional space. iii) The mechanisms making 2ν unity in the two cases above are different and hence ⟨R2⟩ are generally different in these two cases. iv) The parameter z of the two-parameter theory is not a good parameter for analyzing the data near Θ-point.
ASJC Scopus subject areas
- Physics and Astronomy(all)