Programming Chain Distribution of Branched Polymers via Bond Exchange Reactions

Branched chain isomerizable network allows polymers to be programmed into a variety of branched chain distribution (P-i) and branch chain uniformity (alpha) that are challenging to characterize experimentally, leading to difficulties in establishing structure-property relationships. We employ coarse-grained molecular dynamics (CGMD) simulations to demonstrate the equivalence principle for bond exchange reactions (BERs) and propose a theoretical model to describe the P-i and alpha dynamics under BERs. The theoretical model accurately characterizes the intricate time evolution of P-i and alpha by relying solely on BER rates and initial configurations, enabling precise control of P-i and alpha. Furthermore, a concise equation is proposed to describe the P-i and alpha of the BER equilibrium state, revealing the geometric distribution of branched chain, which overthrows the conventional understanding that it obeys a uniform distribution. Finally, taking the example of alpha modulating the toughness, we illustrate how the proposed theoretical model allows for the establishment of structure-property relationships. Overall, this work addresses the challenge of experimentally characterizing P-i and alpha, and introduces a novel research paradigm for establishing structure-property relationships.