Biasing the polymorphism of a semicrystalline covalent polymer by exploiting the microstructure of supramolecular copolymers

Supramolecular copolymers constitute a promising class of modular and dynamic materials. While most efforts thus far have been focused on tailoring their synthesis, structure, and function, their ability to impose order on the surrounding matrix remains poorly understood and relatively unexploited. In this context, we were intrigued by the potential of supramolecular copolymers to guide the outcome of the liquid-solid phase transition of a matrix. We hypothesized that the microstructure of a supramolecular copolymer could influence the local ordering of matrix molecules in the liquid state as it is cooled and solidified, thereby dictating its solid-state structure. Herein, we exemplify this concept using a matrix of isotactic polypropylene (PP) and supramolecular copolymers based on benzene tricarboxamides (BTAs). Two BTA structures were chosen for this study, one that exclusively nucleates the α-form of PP and another that preferentially nucleates the β-form. We demonstrate that the stoichiometric imbalance of the BTA comonomers and their microstructure within the copolymer play crucial roles in biasing the crystallization of the matrix.