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

  • Wenjie Wang

    Ames Laboratory, Iowa State University, Ames National Laboratory

Authors

  • David C Johnston

    Ames Laboratory, Iowa State University, Ames National Laboratory & Iowa State University, Ames National Laboratory and Iowa State University

  • Wenjie Wang

    Ames Laboratory, Iowa State University, Ames National Laboratory

  • Binay P Nayak

    Iowa State University

  • Honghu Zhang

    Brookhaven National Laboratory, NSLS II, Brookhaven National Laboratory

  • Alex Travesset

    Iowa State University and Ames National Laboratory, Ames Lab

  • Surya Mallapragada

    Iowa State University

  • Surya Mallapragada

    Iowa State University