Precise Modulation of Molecular Weight Distribution for Structure Engineering

As one of the most critical molecular parameters, molecular weight distribution has profound impact on structure and properties of polymer. Quantitative and comprehensive understanding, however, has yet to be established, mainly due to the challenge in precise control and regulation of molecular weight distribution. In this work, we demonstrated a robust and effective approach to artificially engineer molecular weight distribution through precise recombination of discrete macromolecules. The width, symmetry, and other characteristics of the distribution can be independently manipulated to achieve absolute control, serving as a model platform for highlighting the importance of chain length heterogeneity on structure engineering. Different from discrete counterparts, each individual component in dispersed samples experiences varied degree of supercooling at a specific crystallization temperature. Non-uniform crystal nucleation and growth kinetics lead to distinct molecular arrangements. This work could bridge the gap between discrete and dispersed macromolecules, providing fundamental perspective on the critical role of molecular weight distribution.