PEG-Grafted Silver Nanoparticles: Implications for Plasmonics and Photonics

Graphs and illustrations of PEG40k-AgNPs
(a) Extracted structure factor profiles for PEG40k-AgNPs with (a) 500 mM K2CO3 at 50 C, (b) 0, and (c) 2 mM PAA2k,. In (a), red arrows indicate the Q positions of higher-orders Bragg diffraction peaks of a hexagonal lattice. Insets in (b) and (c): Peak position, Q, as a function of peak-order with a linear fit with a slope estimation of interparticle distance, d. (d) Schematic illustration for self assembly of PEG40k-AgNPs under the specific solvent condition
Scientific Achievement

Lamellar and hexagonal assemblies of silver nanoparticles (AgNPs) were formed by grafting them with thiolated polyethylene glycol (PEG). Novel two- and three-dimensional assemblies were achieved by controlling differences in core AgNP types and grafting densities.

Significance and Impact

Incomplete grafting of PEG on AgNPs leads to bi-directional bonding among particles and novel assembly structures not observed with PEG-functionalized AuNPs alone. Such control allows for designing and tailoring NPs assembly in photonics, plasmonics, and other applications.

Research Details
  • Small angle Xray scattering (SAXS) at the APS used to monitor the three-dimensional (3D) assemblies in bulk suspensions.
  • K2CO3 induces 2D hexagonal structure at the liquid/vapor interface and 3D hexagonal columnar structure in solutions.

Kim, H. J., Wang, W., Bu, W., Mallapragada, S. K., & Vaknin, D. (2022). Lamellar and hexagonal assemblies of PEG-grafted silver nanoparticles: Implications for plasmonics and photonics. ACS Applied Nano Materials, 5(12), 17556–17564.