# X-ray scattering characterization of iron oxide nanoparticles Langmuir film on water surface and on a solid substrate

## TL;DR

This study uses X-ray techniques to compare the structure of iron oxide nanoparticle films on water and solid substrates, revealing well-ordered monolayers with slight lattice differences and validating the Langmuir-Schaefer method for deposition.

## Contribution

It introduces a combined X-ray reflectometry and scattering approach to analyze nanoparticle films on different substrates, highlighting structural consistency and method validation.

## Key findings

- Nanoparticle films form well-ordered monolayers on both substrates.
- Lattice parameters vary slightly between water and solid substrates.
- Langmuir-Schaefer technique effectively deposits nanoparticles on solids.

## Abstract

In the present study we compare a structure of a Langmuir film assembled from magnetic iron oxide nanoparticles on water surface and a structure of the same film after its transfer to a solid substrate by the Langmuir-Schaefer method. In contrast to most of related studies, where different techniques are used to characterize the films before and after the deposition, we use the same combination of X-ray reflectometry and Grazing Incidence Small-Angle X-ray scattering. In both cases -- on a liquid and on a solid substrate -- the film was identified as a well-ordered monolayer of the nanoparticles laterally organized in a two-dimensional hexagonal lattice. However parameters of the lattice were found to be slightly different depending on the type of the substrate. It is also demonstrated that Langmuir-Schaefer technique is the right way for deposition of such kind of the particles on a solid substrate.