Here, 𝑁 𝐴 is Avogadro's constant. For linear chains, 𝑧 ≈ 7 is a constant in good solvent. The corresponding 𝑧 of star polymers is not known but can be expected to be larger, since the increased compactness of the molecules overcompensates the poorer draining of the solvent and the shift of the universal constant for viscosity with increasing 𝑓. We have computed 𝑧 for all combinations between the polymers and the solvents of our study and obtain 𝑧 = 9.1 ± 0.6 when using 𝜒 𝑇𝑀 . Repeating this analysis with other estimates for the interaction parameter produces a significantly larger scatter for 𝑧 supporting our observation that 𝜒 𝑇𝑀 fits best to the experimental data.