Chemical and Biological Engineering, Materials Science and Engineering, Neuroscience, Ames Laboratory, Physics and Astronomy
Research Focus Area
Advanced and Nanostructured Materials
Journal or Book Title
ACS Applied Nano Materials
We report on the assembly of polymer-grafted nanostructures at the vapor/aqueous interface and in bulk solutions by using synchrotron X-ray diffraction methods. Triangular- and octahedral-shaped gold nanostructures are synthesized and grafted with polyethylene glycol (referred to as PEG-AuNTs and PEG-AuNOh, respectively) and their suspensions are manipulated with salts, (poly)electrolytes that induce interpolymer complexation and HCl to achieve organized assemblies. The assemblies at the vapor/liquid interface are explored by X-ray reflectivity and grazing incidence small angle X-ray scattering. Results show that the PEG-AuNTs and PEG-AuNOh populate the interface, with some degree of orientation with respect to the liquid surface. The resulting assemblies can be tuned by regulating electrolyte and pH levels of the suspensions. Similar tuning also creates three dimensional assemblies that are revealed with solution small angle X-ray scattering. In addition to controlling the 3D aggregates by regulating the (poly)electrolytes and pH levels, we show that raising the temperature of the suspensions from 20 to above 50 $^o$C induces and even improves ordering of the tunable assemblies. Our findings provide tools that can be used to assemble and orient anisotropic nanostructures for potential applications in photonics and plasmonics.
American Chemical Society
Kim, Hyeong Jin; Hossen, Md Mir; Hillier, Andrew C.; Vaknin, David; Mallapragada, Surya K.; and Wang, Wenjie, "Interfacial and Bulk Assembly of Anisotropic Gold Nanostructures: Implications for Photonics and Plasmonics" (2020). Chemical and Biological Engineering Publications. 439.