Optimization in polymer design using connectivity indices

This work addresses the design of polymers with optimal levels of macroscop ic properties through the use of topological indices. Specifically, two zer oth-order and two first-order connectivity indices are for the first time e mployed as descriptors in structure-property correlations in an optimizatio n study. Based on these descriptors, a set of new correlations for heat cap acity, cohesive energy, glass transition temperature, refractive index, and dielectric constant are proposed. These correlations are incorporated into an optimization framework. The proposed mathematical description, utilizin g the concept of a basic group, accounts fully for molecular interconnectiv ity. When the nonconvex terms are appropriately recast in the formulation a s convex inequalities, a convex mixed-integer nonlinear (MINLP) representat ion is obtained. Three example problems highlight the proposed molecular de scription, structure-property correlations, convex MINLP optimization formu lation, and solution technique.