Aggregate Formation of Surface-Modified Nanoparticles in Solvents and Polymer Nanocomposites

TL;DR

This paper introduces a novel combined method using small-angle scattering, simulations, and an algorithm to analyze nanoparticle aggregation in solvents and polymer nanocomposites, revealing how surface chemistry influences dispersion.

Contribution

It presents a new integrated approach for detailed structural analysis of nanoparticle suspensions and nanocomposites, enabling better understanding of surface modification effects.

Findings

Surface chemistry affects nanoparticle dispersion in media.

The method accurately reproduces experimental scattering data.

Dispersion states vary with silane functional groups.

Abstract

A new method based on the combination of small-anglescattering, reverse Monte Carlo simulations, and an aggregate recognition algorithm is proposed to characterize the structure of nanoparticle suspensions in solvents and polymer nanocomposites, allowing detailedstudies of the impact of different nanoparticle surface modifications.Experimental small-angle scattering is reproduced using simulated annealing of configurations of polydisperse particles in a simulation box compatible with the lowest experimental q-vector. Then, properties of interest likeaggregation states are extracted from these configurations and averaged. This approach has been applied to silane surface-modified silica nanoparticles with different grafting groups, in solvents and after casting into polymer matrices.It is shown that the chemistry of the silane function, in particular mono- or trifunctionality possibly related to patch formation, affects the dispersion state in a given medium, in spite of an unchanged alkylchain length. Our approach may be applied to study any dispersion or aggregation state of nanoparticles. Concerningnanocomposites, the method has potential impact on the design of new formulations allowing controlled tuning of nanoparticle dispersion.