Pore size distribution induced by microphase separation: Effect of the leaving group during polycondensation

A mean field theoretical model is developed to investigate the porosity of cross-linked copolymer networks formed by polycondensation. It is found tha t cross-linking induces microphase separation, and when accompanied by poly condensation, the pore size distribution is affected in an unexpected manne r. Pores much larger than the size of the leaving groups are predicted when the leaving group is large. The pore distribution in such cases is found t o be multimodal, exhibiting a peak for small pores, a second narrow peak fo r pores corresponding to the monomer size, and a third peak for very large pores. The model also predicts the extent of microphase separation of the c hemically different monomers as a function of the chemical constitution, th e degree of cross-linking, and the size of the leaving group.