Figure 1

SANS in the dilute limit: The PEG radius of gyration $R_g(c_p,{\mathrm{\Phi }}_F)$, obtained from SANS measurements for Ficoll volume fractions from ${\mathrm{\Phi }}_F=0$ to ${\mathrm{\Phi }}_F=0.30$, is plotted on a logarithmic concentration scale to highlight the concentration $c=0.001{\text{g/cm}}^3$, which is below the $c*$ obtained from diffusion measurements. $R_g(0.001{\text{g/cm}}^3,{\mathrm{\Phi }}_F)$ shows no dependence on ${\mathrm{\Phi }}_F$, consistent with the piecewise fit using the diffusion $c*$ (solid lines) but not with the linear extrapolation (curved dashed lines on the logarithmic concentration scale).