  The equation of state of the osmotic pressure for linear-polymer solutions in
good solvents is universally described by a scaling function. We experimentally
measure the osmotic pressure of the gelation process via osmotic deswelling. We
find that the same scaling function for linear-polymer solutions also describes
the osmotic pressure throughout the gelation process involving both the sol and
gel states. Furthermore, we reveal that the osmotic pressure of polymer gels is
universally governed by the semidilute scaling law of linear-polymer solutions.
