Coil dimensions of macromolecules in the presence of crowding colloids: Impact of crowder size

The theoretical approach predicts that the shrinking of a polymer coil upon adding colloidal particles varies with the size of the colloids. We find coil shrinking is weakest when the colloidal particles are approximately the same size as the Kuhn segment length. The extent of coil shrinking passes a minimum at a specific colloid size relative to the Kuhn segment length, which is confirmed by SCF computations. Comparison with scattering experiments reveals that these experiments corroborate the extent of polymer shrinking at a given volume fraction of colloids. Our theoretical approach reproduces the functional dependence of the collapse on the crowder volume fraction.