Critical phenomena in a polymer-solvent system: slow neutron transmission technique

The slow neutron transmission technique was used to study the shape of the coexistence curves for polystyrene-deuterocyclohexane solution in the fluctuation region of the critical mixing point. Critical indices and amplitudes of the scaled equation for the coexistence curve were determined. From the data obtained, one can conclude that the system belongs to the same universality class as the Ising model. It is shown that the use of different order parameters did not change the numerical values of critical indices of the coexistence curve and caused only the renormalization of amplitudes. Near the critical mixing point the gravity effect was observed, its temperature range being in agreement with theoretical predictions.