| Abstract: | Certain low-angle neutron scattering experiments on bulk protonated polymers containing a fraction of the deuterated species (or vice versa) suggest that clustering of like isotopes is occurring. In order to see whether this is likely, a form for the Helmholtz free energy of mixing is proposed, using thermodynamics and the ideal solution (Flory-Huggins) entropy of mixing. From this free energy the upper consolute point Tc is found. Tc is calculated for several isotopic molecular solutions. The results suggest that while isotope segregation phenomena are impossible for small hydrocarbons, they may become important for large polymer systems. |
