A Strategy Based on Aggregation‐Induced Ratiometric Emission to Differentiate Molecular Weight of Supramolecular Polymers

Abstract

Molecular weight has an important bearing on the properties of supramolecular polymers. However, the intuitive differentiation of the molecular weight of supramolecular polymers remains challenging. Given this situation, establishing a reliable relationship between fluorescence properties and molecular weight may be a promising strategy. Herein, we prepared a supramolecular monomer M1 with aggregation‐induced ratiometric emission characteristics. With the increasing M1 concentration (0.100–100 mM), the average degree of polymerization (DPDOSY) rose from 1.00 to 293. Meanwhile, the color changed from dark blue to cyan, finally to yellow‐green in the same concentration range. Hence, the intuitive relationship between DPDOSY and fluorescence colors was constructed, allowing the visual differentiation of molecular weight. Moreover, the fluorescence color could be regulated by introducing a competitive molecule to induce the depolymerization of supramolecular polymers.

Fluorescence Lifetime-Based Characterization for Supramolecular Polymer Molecular Weight

“…The molecular weight of polymers has a profound impact on their functional performance, physical properties, and processing characteristics. − Characterizing the molecular weight provides valuable insights into the properties of polymers. , In the case of conventional polymers, gel permeation chromatography is commonly used to directly measure molecular weight with precision , However, this method is not suitable for supramolecular polymers, which are a distinct type of polymer formed through noncovalent interactions. − Unlike covalent polymers, supramolecular polymers exhibit dynamic behavior, and their formation is highly dependent on concentration. − Supramolecular polymers exhibit a dynamic nature attributed to the presence of noncovalent interactions, which play a pivotal role in their assembly from monomeric units. Consequently, the formation of supramolecular polymers is highly dependent on concentration. − At lower concentrations, cyclic assemblies or oligomers prevail as the predominant species, while supramolecular polymers emerge at higher concentrations.…”