Stereoisomeric Furan/Maleimide Adducts as Latent Monomers for One-shot Sequence-Controlled Polymerization
As a primary structure, the sequence plays an important role in the hierarchical self-assembly and the performance of polymers. However, the sequence control is a tough challenging, especially for the 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 low temperature, ~40 oC; while the exo-one can only be significantly activated under high temperature, ~110 oC. 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, the sequence-controlled triblock quadripolymer was unprecedentedly created by the stereoisomeric latent monomers via a one-shot feeding of four co-monomers at initial. The stereoisomeric latent monomers reinforced the latent monomer strategy and greatly diversified sequence structures, offering more models for exploring the structure/property relationship.