Aggregation-Induced Emission (AIE) in Polymers: Effect of Polymer size on the Fluorescence of Low Molecular Weight PEG and PPG.

ABSTRACT

Aggregation-induced emission (AIE) is a fascinating phenomenon where specific molecules exhibit enhanced fluorescence upon aggregation. This unique property has revolutionized the design and development of new fluorescent materials for different applications, from biosensors and organic light-emitting diodes (OLEDs) to biomedical imaging and diagnostics. Researchers are creating sensitive and selective sensing platforms, opening new avenues in material science and engineering by harnessing the potential of AIE. To expand the knowledge in this field, this study explored the aggregation-induced emission (AIE) properties of two polymers, namely polyethylene glycol (PEG) and polypropylene glycol (PPG) of low molecular weight (MW) using fluorescence spectroscopy and absorbance (UV). PEG-300 and PPG-725 were the most fluorescent polymers at UV of the ten investigated. Interestingly, AIE did not correlate linearly with molecular weight (MW), and monobutyl ether substitution in PEG with a similar MW substantially altered its AIE. Furthermore, fluorescence precisely quantified low polymer concentrations in water, and non-aqueous solvents suppressed AIE, suggesting potential for AIE manipulation. These findings enhance our understanding of AIE in polymers, fostering the development of novel materials for applications such as biosensors.