Rheological Characterization of Polymeric Frustrated Lewis Pair Networks

Conventional Lewis acids and Lewis bases will react with each other to form thermodynamically stable Lewis adducts which are inherently unreactive. Sterically encumbered Lewis acids and Lewis bases are prevented from forming such adducts, resulting in the formation of frustrated Lewis pairs (FLPs) with latent reactivity. Extending this concept to polymer science permits the development of a new class of responsive, functional, self-healing materials. Here, we report the rheology of fully macromolecular FLPs based on both styrene and methyl methacrylate (MMA) backbones. When reacted with small molecule cross-linkers, a dynamic network is formed which is both heat-responsive and self-healing. The effect of the polymer backbone and cross-linking density on the formed networks is significant. First generation polymeric FLPs behave in a similar way to the noncovalently linked supramolecular assemblies, where switching from styrene to MMA co-monomers creates stiffer polymer networks as the likelihood of chain entanglements increased with a more flexible backbone.