 Solution

For a concentration blob with $g$ ideal segments, $\xi \sim a\sqrt{g}$ and concentration matching gives $\varphi \sim g{a}^3/{\xi }^3\sim g^{-1/2}$. Thus the concentration-blob size in a theta solvent isThe whole chain contains about ten blobs, so the separation of scales is moderate. Below $\xi$, theta-solvent segments have ideal chain statistics; above it, screening also gives Gaussian random-walk statistics for the sequence of blobs. There is no good-solvent self-avoiding regime to insert in this particular theta-solvent calculation. Density correlations and segment dynamics can still cross over at the blob scale.