Concentration-blob size in a theta solvent
= Concentration-blob size in a theta solvent
{title2=$\xi\sim v_0/(b^2\phi)$}
For an <ideal chain> inside a blob, $\nu=1/2$ and $\xi\sim b\sqrt g$. Together with $\phi\sim gv_0/\xi^3$, this gives the displayed concentration-blob size. Under the site-volume approximation $v_0\sim b^3$, $\xi\sim b/\phi$ and $g\sim\phi^{-2}$. The estimate describes local overlap rather than the full chain size and requires $1\ll g\ll N$ for a well-developed semidilute regime.