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arXiv · 2410.05456

Effect of Grafting Density on the Two-dimensional Assembly of Nanoparticles

Binay P. Nayak·James Ethan Batey·Hyeong Jin Kim·Wenjie Wang·Wei Bu·Honghu Zhang·Surya K. Mallapragada·David Vaknin
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Abstract

Employing grazing-incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that films composed of polyethylene glycol (PEG)-grafted silver nanoparticles (AgNP) and gold nanoparticles (AuNP), as well as their binary mixtures, form highly stable hexagonal structures at the vapor-liquid interface. These nanoparticles exhibit remarkable stability under varying environmental conditions, including changes in pH, mixing concentration, and PEG chain length. Short-chain PEG grafting produces dense, well-ordered films, while longer chains produce more complex, less dense quasi-bilayer structures. AuNPs exhibit higher grafting densities than AgNPs, leading to more ordered in-plane arrangements. In binary mixtures, AuNPs dominate the population at the surface, while AgNPs integrate into the system, expanding the lattice without forming a distinct binary superstructure. These results offer valuable insights into the structural behavior of PEG-grafted nanoparticles and provide a foundation for optimizing binary nanoparticle assemblies for advanced nanotechnology applications.

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Binay P. Nayak, James Ethan Batey, Hyeong Jin Kim, Wenjie Wang, Wei Bu, Honghu Zhang, Surya K. Mallapragada, David Vaknin. 2024-10-07. Effect of Grafting Density on the Two-dimensional Assembly of Nanoparticles. https://arxiv.org/abs/2410.05456

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