Investigating AIE behaviors of amphiphilic AIEgen-based polymers through self-assembly architectures and hydrophobic core arrangements

Abstract

Nanoscale polymersomes showing a prominent aggregation-induced emission (AIE) effect have enormous potential in biomedical applications. In this study, three types of amphiphilic polymers were synthesized using reversible addition–fragmentation chain transfer self-condensing vinyl polymerization. These polymers had linear, branched, and star-like structures, and were composed of hydrophobic and hydrophilic units, namely (2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene (TPEE) and N,N-dimethylacrylamide (DMA), respectively. We found that when the ratio of TPEE and DMA was 3 : 1 (n/n), the star-like polymers showed significantly stronger emission than linear and branched polymers, due to tighter aggregation of TPEE in the polymersomes derived from intermolecular self-assembly of the star-like polymers. However, when the hydrophilic chain length was shortened, the AIE behavior of the star-like polymers was weaker than that of the linear polymers, possibly due to greater steric hindrance of TPEE during the transformation of micelles to vesicles within the linear polymers. We also employed the star-like polymer-derived nanoparticles for living cell imaging with two types of cells (A549 and HepG2). This study offers considerable insights into designing an AIE polymer structure for better emission behaviors.