Stereoisomeric furan/maleimide adducts as latent monomers for one-shot sequence-controlled polymerization

Abstract

As a primary structure, the sequence plays an important role in the hierarchical self-assembly and the performance of polymers. However, sequence control is a tough challenge, especially for chain polymerization. Herein, toward more diversified sequence structures, two stereoisomeric furan/maleimide adducts, i.e., endo- and exo-isomers were introduced as latent monomers. The endo-latent monomer can be activated under a low temperature, ∼40 °C, while the exo-isomer can only be significantly activated under a high temperature, ∼110 °C. The distinct temperature of maleimide activation (or deprotection) enabled the selective release of maleimide by finely tuning the polymerization temperature. The sequence structures were thus greatly enriched by manipulating the temperature change mode, time of each temperature slot, and feed ratio of co-monomers. Here, a sequence-controlled triblock quadripolymer was unprecedentedly created from the stereoisomeric latent monomers via one-shot feeding of four co-monomers at the beginning. The stereoisomeric latent monomers reinforced the latent monomer strategy and led to greatly diversified sequence structures, offering more models for exploring the structure/property relationship.