3D Assembly of Gold Nanorods

depiction of self-assembling gold nanorods
Gold nanorods functionalized with poly(ethylene glycol) (PEG) self-assembled in aqueous solutions  by  electrostatic interactions  and interpolymer complexation processes. The quality and stability of these tunable lattices formed by self-assembly change with temperature .

Assembling gold nanorods (AuNRs) into ordered structures that can exhibit enhanced and variable optical and electronic properties has received a lot of attention for their potential applications in optics, electronics, sensing, and catalysis. Even though many methods have been developed for assembly and crystallization of AuNRs, determinative control over the ordered AuNRs structures is still a challenge. Here, we report on controlling the self-assembly of AuNRs grafted with polyethylene glycol (PEG-AuNRs) driven by the interplay of temperature, salt concentration, pH level, and interpolymer complexation (IPC) between PEG and poly(acrylic acid) . Small angle X-ray scattering reveals that the quality and stability of the assemblies into the hexagonal columnar phases increases with temperature. Moreover, this study shows that the lattice constant of the ordered structures is tunable over a wide range of values of pH and salt concentrations by the interaction between electrostatic and hydrophobic effects.

H.J. Kim, W. Wang, A. Travesset, S.K. Mallapragada and D. Vaknin. Temperature-Induced Tunable Assembly of Columnar Phases of Nanorods. ACS Nano, 14, 6007 (2020)