Salt Mediated Self-Assembly of Poly(ethylene glycol)-Functionalized Gold Nanorods
Hossen, Md. Mir
Although challenging, assembling and orienting non-spherical nanomaterials into two- and three-dimensional (2D and 3D) ordered arrays can facilitate versatile collective properties by virtue of their shape-dependent properties that cannot be realized with their spherical counterparts. Here, we report on the self-assembly of gold nanorods (AuNRs) into 2D films at the vapor/liquid interface facilitated by grafting them with poly(ethylene glycol) (PEG). Using surface sensitive synchrotron grazing incidence small angle X-ray scattering (GISAXS) and specular X-ray reflectivity (XRR), we show that PEG-AuNRs in aqueous suspensions migrate to the vapor/liquid interface in the presence of salt, forming a uniform monolayer with planar-to-surface orientation. Furthermore, the 2D assembled PEG functionalized AuNRs exhibit short range order into rectangular symmetry with side-by-side and tail-to-tail nearest-neighbor packing. The effect of PEG chain length and salt concentration on the 2D assembly are also reported.
This article is published as Kim, Hyeong Jin, Wenjie Wang, Wei Bu, Md Mir Hossen, Alejandra Londono-Calderon, Andrew C. Hillier, Tanya Prozorov, Surya Mallapragada, and David Vaknin. "Salt Mediated Self-Assembly of poly (ethylene glycol)-functionalized Gold nanorods." Scientific Reports 9, no. 1 (2019): 1-9. DOI: 10.1038/s41598-019-56730-2. Posted with permission.