Binary superlattices formed by charged grafted gold nano-particles
ORAL
Abstract
Taking advantage of the aqueous biphasic behavior of polyethylene glycol (PEG), it has been shown that gold nanoparticles (AuNPs) grafted with PEG (PEG-AuNPs) form two- and three-dimensional crystalline structures (including binary structures) by varying salinity and temperature of the suspensions. To extend the control over binary superlattices, we introduce charged end groups to PEG, in this case, carboxylic (-COOH) and amine (-NH2) groups. We show that the effective surface charge per grafted nanoparticle can be tuned by pH leading to assembly into complex super-structures. Using small-angle X-ray scattering (SAXS) technique, we show that by mixing oppositely charged PEG-AuNPs, i.e., COOH-PEG-AuNPs and NH2-PEG-AuNPs, a few binary cubic superlattices can be formed at room temperature by manipulating mixing ratios and pH level.
*Work at Ames National Laboratory is supported by US Department of Energy and Basic Sciences (DOE) DE- AC02-07CH11358. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. DOE Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. This research used resources of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.
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Presenters
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Wenjie Wang
- Ames Laboratory, Iowa State University
- Ames National Laboratory