2. ABSTRACT
Due to their tailorable morphology, silica nanoparticles (SNPs) have recently
attracted widespread attention because they can be used in many emerging
areas. Over the past decade, important work has been done on novel
processing methodologies to prepare SNPs, which have resulted in better
control over the size, shape, porosity, and notable improvements in their
physio-chemical properties. Microemulsions are a simple and widely used
method of preparing silica nanoparticles.
order to effectively use silica nanoparticles (SNs) in catalyst, adsorption,
polymer filler, optical devices, bio-imaging, drug delivery, and biomedical
applications, it is becoming more and more crucial to have good control over
their morphology, particle size, uniformity, and dispersity. It is therefore
desirable to monitor the synthesis process in real time to unravel the
mechanisms behind the formation of silica nanoparticles and to promote their
controllable synthesis.
3. INTRODUCTION
Since silica nanoparticles are highly dependent on structural characteristics such as size, shape, and so
forth perfect control of the structure and quality of manufactured silica nanoparticles has emerged as
an essential goal of nanoscience research. As a result, researchers have devised several ways for
controlling nanoparticle synthesis including the template method, microemulsion method, sol–gel
method, and many others. Among them, Microemulsions are one of the most convenient and widely
used methods for the synthesis of silica nanoparticles. Due to its ease and versatility, it is the most
popular method for controlling the fabrication of nanostructures. Typically, two microemulsions
containing two different reactants are mixed in the microemulsion method to synthesize silica
nanoparticles, and the reaction between the reactants is triggered by the collision of micellar droplets
in the system, which leads to the nucleation and growth of silica nanoparticles. However, the process
of forming silica nanoparticles is extremely complex since it takes place under defined environmental
conditions and non-equilibrium conditions, even though the chemical reactions are usually
straightforward.
4. SYNTHESIS OF NANOPARTICLES
A growing number of researchers are working on the synthesis of nanoscale metals using chemical,
physical, and green synthesis methods. Synthesis techniques play a key role in controlling nanoparticle
characteristics such as morphology, size, structure, and performance.
Silica nanoparticles' electrochemical and physiochemical properties, as well as their optical and
electrical properties, are also affected.
The features of silica nanoparticles are sometimes retained after they precipitate out of suspensions
when they are coated.
6. Synthesis of silica nanoparticles by physical methods involves applying external forces, such as heat
or mechanical energy, to facilitate the formation of the particles. These methods include evaporation
condensation method, physical pulverization method, mechanical ball milling method and ion
sputtering method
1.PHYSICAL METHODS
1.Evaporation and condensation method
2.Physical crushing method
3.Mechanical ball milling method
4.Ion sputtering technique
7. 1.Evaporation and condensation
The evaporative condensation method, which has
a wide range of applications, involves heating
the original material, evaporating it, and then
condensing it with the addition of inert gas to
achieve silica nanoparticles.
2.Physical crushing method
Using mechanical tension from outside the object
being crushed, solid material particles are first
deformed and then crushed to the desired size.
3.Mechanical ball milling method
This technique uses balls to crush reactants into
the desired size using mechanical force. It is
frequently used to reduce bulky solids into tiny
particles.
4.Ion sputtering technique
In this technique, an applied electric field is used
to ionize argon or other inert gases, creating the
glow discharge phenomena. The particles
produced by the ionization then assault the
target, sputtering out and depositing on it.
8. 2.CHEMICAL METHODS
Chemical reactions are employed to synthesize silica nanoparticles using
chemical methods. These methods include sol–gel method, microemulsion
method, electrolysis method, chemical vapor deposition method.
1.Sol-gel method
This method is the so-called “bottom-
up” nanoparticle preparation method,
that is, the process of preparing solid
silica nanoparticles from small
molecules. The process involves
converting the monomer into a colloidal
solution (Sol), which acts as a precursor
to discrete particles or network
polymers (or gels), typically precursors
of metalloalkalks
2.Microemulsion method
this method is a simple and widely used controllable
nanoparticle synthesis method developed in recent years,
generally used to prepare silica nanoparticles is generally
W/O type microemulsion (reversed-phase microemulsion),
the “water core” as a reaction site for the generation of silica
nanoparticles (often called “micro-reactor”), the product can
only grow in a limited space because of the surfactant and
cosurfactant bound so that the nanoparticle size can be
controlled, the particle size of the silica nanoparticles
prepared by this method is small, The distribution is
uniform, and the product is easy to achieve high
purification, and the obtained product monodispersity.
9. 3.Electrolysis method
The electrolysis method usually
includes two methods: aqueous solution
and molten salt electrolysis. Electrolysis
is a technique that uses direct current to
drive non-spontaneous chemical
reactions that separate elements from
natural sources such as ores.
4.Chemical vapor deposition
This method refers to the process of generating
silica nanoparticles through chemical reactions on
the substrate under heating conditions. This method
is widely used in the preparation of silica
nanoparticles
10. To improve systematic studies on the influence of surfactant types on nanoparticle formation, non-
ionic surfactants can be included in microemulsions formed by non-ionic surfactants. Due to the
limitations of the instrument, in-situ and real-time monitoring of ionic surfactant microemulsion
synthesis silica nanoparticles at different temperatures was not possible, so subsequent
experiments could be affected by temperature.
In the last few decades, microemulsions have been a highly relevant and promising field of study
for the development of a wide range of applications, including food science, detergents, and
cosmetics, as well as drug delivery and nanoparticle synthesis. In addition to broadening the
application scope of dielectric spectroscopy, this topic has also provided a deeper understanding of
the mechanisms involved in the formation of silica nanoparticles synthesized through
microemulsions. In spite of this, many areas remain to be explored.
CONCLUSION
