Physisorption of Poly(ethylene glycol) on Inorganic Nanoparticles

Poly(ethylene glycol) (PEG) is the most widely used polymer to decorate inorganic nanoparticles (NPs) by the grafting-to method for antifouling properties. PEG also shows diverse supramolecular interactions with nanoparticle surfaces and polar molecules, suggesting that the physisorption between PEG chains and NPs cannot be ignored in the grafting-to process. However, the effect of physisorption of PEG to NPs on the process of chemisorption has been rarely studied. Herein, we report that unfunctionalized PEG is physically adsorbed on various NPs by polyvalent supramolecular interactions, adopting loop-and-train-tail conformations. We investigated the effect of molecular weight of PEG and ligands of the NPs on the conformation of PEG chains by experimental methods and simulation. It is demonstrated that the physisorption of PEG on NPs can facilitate the chemisorption in the initial stages but delays it in the later stages during the grafting-to process. This work provides a deeper understanding of the conformation of physisorbed PEG on NPs and the relationship between physisorption and chemisorption.

Automated summary

This study reports that unfunctionalized PEG is physically adsorbed on various NPs through supramolecular interactions, and investigates the effect of PEG molecular weight and NP ligands on the conformation of PEG chains. The results demonstrate that the physisorption of PEG on NPs can facilitate chemisorption in the initial stages but delay it in the later stages.