Preparation of compact nanoparticle clusters from polyethylene glycol-coated gold nanoparticles by fine-tuning colloidal interactions

Zámbó, Dániel and Radnóczi, György Zoltán and Deák, András (2015) Preparation of compact nanoparticle clusters from polyethylene glycol-coated gold nanoparticles by fine-tuning colloidal interactions. LANGMUIR, 31 (9). pp. 2662-2668. ISSN 0743-7463

Text Za_mbo__et_al.___2015___Preparation_of_Compact_Nanoparticle_Clusters_from__u.pdf Restricted to Repository staff only Download (2MB) | Request a copy

Abstract

Low-molecular weight polyethylene glycol (PEG) has a lower critical solution temperature well outside the boiling point of water at ambient pressure, but it can be reduced at high ionic strengths. We extend this concept to trigger the clustering of gold nanoparticles through the control of colloidal interactions. At high ionic strengths, low-molecular weight (<2000 Da) mPEG-SH-modi fi ed gold nanoparticles show clustering with an increase in the solution temperature. The clustering temperature decreases with an increasing ionic strength. The clustering is attributed to the delicate interplay between the high ionic strength and elevated temperature and is interpreted in terms of chain collapse of the surface-grafted PEG molecules. The chain collapse results in a change in the steric interaction term, whereas the high ionic strength eliminates the double-layer repulsion between the particles. The observations are backed by nanoparticle interaction model calculations. We found that the intermediate attractive potential on the order of a few kT allows the experimental fabrication of compact nanoparticle clusters in agreement with theoretical predictions. The approach presented here has the potential to be extended on the externally triggered preparation of nanoparticle clusters wit different types of nanoparticles.

Actions (login required)

Edit Item