Original Article:
Polyethylene glycol (PEG) derived carbon dots: Preparation and applications
Zhili Peng, et al.
Applied Materials Today, 2020, 20, 100677.
10.1016/j.apmt.2020.100677
Polyethylene glycol (PEG), as a non-toxic, non-immunogenic and highly water-soluble polymer, is widely used in the pegylation of protein/peptide drugs and traditional nanoparticles. Recently, PEG has attracted attention for its unique ability to enhance C-dot fluorescence emission and elucidate the mechanism of C-dot formation and photoluminescence. Here, we highlight recent advances in the synthesis of carbon dots with PEG as a passivation agent, solvent/substrate, and sole carbon precursor.
1) PEG as a passivation agent in the synthesis of C-dots
In most syntheses, surface passivation is necessary to enhance the photoluminescence (PL) performance of C-dots. The passivation of the C-dots aims to increase the PL intensity by forming a thin insulating covering "layer" to prevent energy loss with emission. Passivator selection typically focuses on polymers that do not contain visible chromophores, such as PEG. Since 2006, PEG has been widely used as a passivating agent to passivate C-dots. Selective examples of PEG-passivated C-dots are shown as table.
2) PEG as a solvent/substrate in C-dots synthesis
PEG is amphiphilic and therefore soluble in water and many organic solvents (i.e. CH3CH2OH, CH2Cl2, CH3Cl, etc.), making it an ideal reaction medium. For example, Lehmacher and Feldmann reported the synthesis of red-emitting carbon dots from 1,2,4,5-tetracyanobenzene, in which PEG400 was chosen as the solvent while also acting as a surface stabilizer/passivator.
3) PEG as a carbon precursor for C-dots synthesis
Chemically and structurally, PEG is a good carbon precursor for carbon dot synthesis. Inspired by numerous reports on C-dots, Feldmann's team was able to trace the unexpected fluorescence to carbon dots formed by the thermal decomposition of PEG during NP synthesis.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM25322683-1 | Polyethylene glycol,mw 6800(8,000cs(99°c)) |  |
25322-68-3 | Price |
| ACM25322683-8 | Polyethylene glycol,mw 400(7.4cs(99°c)) | |
25322-68-3 | Price |
