# Silica Nanoparticles vs Nanocapsules from Dye-Stabilized Emulsions: Role of the Comonomer

## TL;DR

This paper explores how different chemical precursors affect the formation of silica nanoparticles or nanocapsules in dye-stabilized emulsions.

## Contribution

The study reveals how the sol–gel reaction kinetics influence the morphology of silica nanostructures.

## Key findings

- Congo red stabilizes emulsions to form nanoparticles and nanocapsules.
- Faster sol–gel reactions favor nanocapsule formation over nanoparticles.
- Molecular structure and temperature impact the final nanostructure morphology.

## Abstract

Dye-stabilized o/w miniemulsions offer an effective platform
for
synthesizing silica nano-objects via a sol–gel process at the
oil–water interface. The choice of the organotrialkoxysilane
precursor has a significant impact on the morphology of the resulting
silica structures. When Congo red is used as a stabilizer, narrowly
distributed nanoparticles below 30 nm and nanocapsules with diameters
under 500 nm are formed. The subtle influence of the selected monomer
is linked to the kinetics of the sol–gel process, which depend
on factors such as molecular structure, comonomer content, and temperature.
Factors that accelerate the sol–gel reaction, such as lower
steric demand, higher water solubility of the precursor, and temperature
increase, favor capsule formation, while slower reactions tend to
produce particles instead.