Liquid-liquid phase separation by nucleation and growth in solutions of poly(2,6 dimethyl-1,4 phenylene oxide) in toluene

In solutions of poly(2,6 dimethyl-1,4 phenylene oxide) in toluene, the nucleation of the newly formed phase during liquid-liquid phase separation takes place after induction periods which vary between several minutes (at temperatures close to the spinodal) and several hours (at temperatures close to the cloudpoint). The growth of the nuclei in the initial stages is diffusion controlled. The diffusion coefficients and the activation energy of diffusion were calculated. From these values, together with the calculated volume free energies and the experimental induction times, an estimate could be made of the size of a critical nucleus and of the surface free energy of the nuclei.