Einstein-Batchelor, equation

If the molecules are considered to behave like hard spheres, which implies that the entrained solvent molecules move with the polymer coil, then the Einstein-Batchelor equation may be applied, which is as follows ... 

Substitution of Equation 10.9 for the volume fraction of spheres into the Einstein-Batchelor equation along with the use of the root mean squared end-to-end distance for the sphere diameter gives rise to Equation 10.10. 

---